draft-ietf-acme-acme-18.txt   rfc8555.txt 
ACME Working Group R. Barnes Internet Engineering Task Force (IETF) R. Barnes
Internet-Draft Cisco Request for Comments: 8555 Cisco
Intended status: Standards Track J. Hoffman-Andrews Category: Standards Track J. Hoffman-Andrews
Expires: June 23, 2019 EFF ISSN: 2070-1721 EFF
D. McCarney D. McCarney
Let's Encrypt Let's Encrypt
J. Kasten J. Kasten
University of Michigan University of Michigan
December 20, 2018 March 2019
Automatic Certificate Management Environment (ACME) Automatic Certificate Management Environment (ACME)
draft-ietf-acme-acme-18
Abstract Abstract
Public Key Infrastructure X.509 (PKIX) certificates are used for a Public Key Infrastructure using X.509 (PKIX) certificates are used
number of purposes, the most significant of which is the for a number of purposes, the most significant of which is the
authentication of domain names. Thus, certification authorities authentication of domain names. Thus, certification authorities
(CAs) in the Web PKI are trusted to verify that an applicant for a (CAs) in the Web PKI are trusted to verify that an applicant for a
certificate legitimately represents the domain name(s) in the certificate legitimately represents the domain name(s) in the
certificate. Today, this verification is done through a collection certificate. As of this writing, this verification is done through a
of ad hoc mechanisms. This document describes a protocol that a CA collection of ad hoc mechanisms. This document describes a protocol
and an applicant can use to automate the process of verification and that a CA and an applicant can use to automate the process of
certificate issuance. The protocol also provides facilities for verification and certificate issuance. The protocol also provides
other certificate management functions, such as certificate facilities for other certificate management functions, such as
revocation. certificate revocation.
RFC EDITOR: PLEASE REMOVE THE FOLLOWING PARAGRAPH: The source for
this draft is maintained in GitHub. Suggested changes should be
submitted as pull requests at https://github.com/ietf-wg-acme/acme
[1]. Instructions are on that page as well. Editorial changes can
be managed in GitHub, but any substantive change should be discussed
on the ACME mailing list (acme@ietf.org).
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This is an Internet Standards Track document.
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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Internet-Drafts are draft documents valid for a maximum of six months This document is a product of the Internet Engineering Task Force
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Internet Standards is available in Section 2 of RFC 7841.
This Internet-Draft will expire on June 23, 2019. Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
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Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
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Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction ....................................................4
2. Deployment Model and Operator Experience . . . . . . . . . . 5 2. Deployment Model and Operator Experience ........................5
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 7 3. Terminology .....................................................7
4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7 4. Protocol Overview ...............................................7
5. Character Encoding . . . . . . . . . . . . . . . . . . . . . 10 5. Character Encoding .............................................10
6. Message Transport . . . . . . . . . . . . . . . . . . . . . . 10 6. Message Transport ..............................................10
6.1. HTTPS Requests . . . . . . . . . . . . . . . . . . . . . 10 6.1. HTTPS Requests ............................................10
6.2. Request Authentication . . . . . . . . . . . . . . . . . 11 6.2. Request Authentication ....................................11
6.3. GET and POST-as-GET Requests . . . . . . . . . . . . . . 12 6.3. GET and POST-as-GET Requests ..............................13
6.4. Request URL Integrity . . . . . . . . . . . . . . . . . . 13 6.4. Request URL Integrity .....................................13
6.4.1. "url" (URL) JWS Header Parameter . . . . . . . . . . 14 6.4.1. "url" (URL) JWS Header Parameter ...................14
6.5. Replay protection . . . . . . . . . . . . . . . . . . . . 14 6.5. Replay Protection .........................................14
6.5.1. Replay-Nonce . . . . . . . . . . . . . . . . . . . . 15 6.5.1. Replay-Nonce .......................................15
6.5.2. "nonce" (Nonce) JWS Header Parameter . . . . . . . . 15 6.5.2. "nonce" (Nonce) JWS Header Parameter ...............16
6.6. Rate Limits . . . . . . . . . . . . . . . . . . . . . . . 15 6.6. Rate Limits ...............................................16
6.7. Errors . . . . . . . . . . . . . . . . . . . . . . . . . 16 6.7. Errors ....................................................16
6.7.1. Subproblems . . . . . . . . . . . . . . . . . . . . . 18 6.7.1. Subproblems ........................................18
7. Certificate Management . . . . . . . . . . . . . . . . . . . 19 7. Certificate Management .........................................20
7.1. Resources . . . . . . . . . . . . . . . . . . . . . . . . 19 7.1. Resources .................................................20
7.1.1. Directory . . . . . . . . . . . . . . . . . . . . . . 22 7.1.1. Directory ..........................................23
7.1.2. Account Objects . . . . . . . . . . . . . . . . . . . 24 7.1.2. Account Objects ....................................24
7.1.3. Order Objects . . . . . . . . . . . . . . . . . . . . 25 7.1.3. Order Objects ......................................26
7.1.4. Authorization Objects . . . . . . . . . . . . . . . . 28 7.1.4. Authorization Objects ..............................28
7.1.5. Challenge Objects . . . . . . . . . . . . . . . . . . 30 7.1.5. Challenge Objects ..................................30
7.1.6. Status Changes . . . . . . . . . . . . . . . . . . . 30 7.1.6. Status Changes .....................................30
7.2. Getting a Nonce . . . . . . . . . . . . . . . . . . . . . 32 7.2. Getting a Nonce ...........................................34
7.3. Account Management . . . . . . . . . . . . . . . . . . . 33 7.3. Account Management ........................................34
7.3.1. Finding an Account URL Given a Key . . . . . . . . . 35 7.3.1. Finding an Account URL Given a Key .................36
7.3.2. Account Update . . . . . . . . . . . . . . . . . . . 36 7.3.2. Account Update .....................................37
7.3.3. Changes of Terms of Service . . . . . . . . . . . . . 36 7.3.3. Changes of Terms of Service ........................38
7.3.4. External Account Binding . . . . . . . . . . . . . . 37 7.3.4. External Account Binding ...........................38
7.3.5. Account Key Roll-over . . . . . . . . . . . . . . . . 39 7.3.5. Account Key Rollover ...............................40
7.3.6. Account Deactivation . . . . . . . . . . . . . . . . 42 7.3.6. Account Deactivation ...............................43
7.4. Applying for Certificate Issuance . . . . . . . . . . . . 43 7.4. Applying for Certificate Issuance .........................44
7.4.1. Pre-Authorization . . . . . . . . . . . . . . . . . . 47 7.4.1. Pre-authorization ..................................49
7.4.2. Downloading the Certificate . . . . . . . . . . . . . 49 7.4.2. Downloading the Certificate ........................51
7.5. Identifier Authorization . . . . . . . . . . . . . . . . 51 7.5. Identifier Authorization ..................................53
7.5.1. Responding to Challenges . . . . . . . . . . . . . . 53 7.5.1. Responding to Challenges ...........................54
7.5.2. Deactivating an Authorization . . . . . . . . . . . . 55 7.5.2. Deactivating an Authorization ......................57
7.6. Certificate Revocation . . . . . . . . . . . . . . . . . 56 7.6. Certificate Revocation ....................................58
8. Identifier Validation Challenges . . . . . . . . . . . . . . 58 8. Identifier Validation Challenges ...............................60
8.1. Key Authorizations . . . . . . . . . . . . . . . . . . . 60 8.1. Key Authorizations ........................................62
8.2. Retrying Challenges . . . . . . . . . . . . . . . . . . . 60 8.2. Retrying Challenges .......................................63
8.3. HTTP Challenge . . . . . . . . . . . . . . . . . . . . . 61 8.3. HTTP Challenge ............................................63
8.4. DNS Challenge . . . . . . . . . . . . . . . . . . . . . . 64 8.4. DNS Challenge .............................................66
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 65 9. IANA Considerations ............................................68
9.1. MIME Type: application/pem-certificate-chain . . . . . . 65 9.1. Media Type: application/pem-certificate-chain .............68
9.2. Well-Known URI for the HTTP Challenge . . . . . . . . . . 67 9.2. Well-Known URI for the HTTP Challenge .....................69
9.3. Replay-Nonce HTTP Header . . . . . . . . . . . . . . . . 67 9.3. Replay-Nonce HTTP Header ..................................69
9.4. "url" JWS Header Parameter . . . . . . . . . . . . . . . 67 9.4. "url" JWS Header Parameter ................................70
9.5. "nonce" JWS Header Parameter . . . . . . . . . . . . . . 68 9.5. "nonce" JWS Header Parameter ..............................70
9.6. URN Sub-namespace for ACME (urn:ietf:params:acme) . . . . 68 9.6. URN Sub-namespace for ACME (urn:ietf:params:acme) .........70
9.7. New Registries . . . . . . . . . . . . . . . . . . . . . 68 9.7. New Registries ............................................71
9.7.1. Fields in Account Objects . . . . . . . . . . . . . . 69 9.7.1. Fields in Account Objects ..........................71
9.7.2. Fields in Order Objects . . . . . . . . . . . . . . . 70 9.7.2. Fields in Order Objects ............................72
9.7.3. Fields in Authorization Objects . . . . . . . . . . . 71 9.7.3. Fields in Authorization Objects ....................73
9.7.4. Error Types . . . . . . . . . . . . . . . . . . . . . 72 9.7.4. Error Types ........................................74
9.7.5. Resource Types . . . . . . . . . . . . . . . . . . . 72 9.7.5. Resource Types .....................................74
9.7.6. Fields in the "meta" Object within a Directory Object 73 9.7.6. Fields in the "meta" Object within a
9.7.7. Identifier Types . . . . . . . . . . . . . . . . . . 74 Directory Object ...................................75
9.7.8. Validation Methods . . . . . . . . . . . . . . . . . 74 9.7.7. Identifier Types ...................................76
10. Security Considerations . . . . . . . . . . . . . . . . . . . 76 9.7.8. Validation Methods .................................76
10.1. Threat Model . . . . . . . . . . . . . . . . . . . . . . 76 10. Security Considerations .......................................78
10.2. Integrity of Authorizations . . . . . . . . . . . . . . 78 10.1. Threat Model .............................................78
10.3. Denial-of-Service Considerations . . . . . . . . . . . . 81 10.2. Integrity of Authorizations ..............................80
10.4. Server-Side Request Forgery . . . . . . . . . . . . . . 82 10.3. Denial-of-Service Considerations .........................83
10.5. CA Policy Considerations . . . . . . . . . . . . . . . . 82 10.4. Server-Side Request Forgery ..............................84
11. Operational Considerations . . . . . . . . . . . . . . . . . 84 10.5. CA Policy Considerations .................................84
11.1. Key Selection . . . . . . . . . . . . . . . . . . . . . 84 11. Operational Considerations ....................................86
11.2. DNS security . . . . . . . . . . . . . . . . . . . . . . 85 11.1. Key Selection ............................................86
11.3. Token Entropy . . . . . . . . . . . . . . . . . . . . . 85 11.2. DNS Security .............................................87
11.4. Malformed Certificate Chains . . . . . . . . . . . . . . 86 11.3. Token Entropy ............................................88
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 86 11.4. Malformed Certificate Chains .............................88
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 87 12. References ....................................................88
13.1. Normative References . . . . . . . . . . . . . . . . . . 87 12.1. Normative References .....................................88
13.2. Informative References . . . . . . . . . . . . . . . . . 90 12.2. Informative References ...................................92
13.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 91 Acknowledgements ..................................................94
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 92 Authors' Addresses ................................................95
1. Introduction 1. Introduction
Certificates [RFC5280] in the Web PKI are most commonly used to Certificates [RFC5280] in the Web PKI are most commonly used to
authenticate domain names. Thus, certification authorities (CAs) in authenticate domain names. Thus, certification authorities (CAs) in
the Web PKI are trusted to verify that an applicant for a certificate the Web PKI are trusted to verify that an applicant for a certificate
legitimately represents the domain name(s) in the certificate. legitimately represents the domain name(s) in the certificate.
Different types of certificates reflect different kinds of CA Different types of certificates reflect different kinds of CA
verification of information about the certificate subject. "Domain verification of information about the certificate subject. "Domain
Validation" (DV) certificates are by far the most common type. The Validation" (DV) certificates are by far the most common type. The
only validation the CA is required to perform in the DV issuance only validation the CA is required to perform in the DV issuance
process is to verify that the requester has effective control of the process is to verify that the requester has effective control of the
domain [CABFBR]. The CA is not required to attempt to verify the domain [CABFBR]. The CA is not required to attempt to verify the
requester's real-world identity. (This is as opposed to requester's real-world identity. (This is as opposed to
"Organization Validation" (OV) and "Extended Validation" (EV) "Organization Validation" (OV) and "Extended Validation" (EV)
certificates, where the process is intended to also verify the real- certificates, where the process is intended to also verify the real-
world identity of the requester.) world identity of the requester.)
Existing Web PKI certificate authorities tend to use a set of ad hoc Existing Web PKI certification authorities tend to use a set of ad
protocols for certificate issuance and identity verification. In the hoc protocols for certificate issuance and identity verification. In
case of DV certificates, a typical user experience is something like: the case of DV certificates, a typical user experience is something
like:
o Generate a PKCS#10 [RFC2986] Certificate Signing Request (CSR). o Generate a PKCS#10 [RFC2986] Certificate Signing Request (CSR).
o Cut-and-paste the CSR into a CA's web page. o Cut and paste the CSR into a CA's web page.
o Prove ownership of the domain by one of the following methods: o Prove ownership of the domain(s) in the CSR by one of the
following methods:
* Put a CA-provided challenge at a specific place on the web * Put a CA-provided challenge at a specific place on the web
server. server.
* Put a CA-provided challenge in a DNS record corresponding to * Put a CA-provided challenge in a DNS record corresponding to
the target domain. the target domain.
* Receive a CA-provided challenge at a (hopefully) administrator- * Receive a CA-provided challenge at (hopefully) an
controlled email address corresponding to the domain and then administrator-controlled email address corresponding to the
respond to it on the CA's web page. domain, and then respond to it on the CA's web page.
o Download the issued certificate and install it on their Web o Download the issued certificate and install it on the user's Web
Server. Server.
With the exception of the CSR itself and the certificates that are With the exception of the CSR itself and the certificates that are
issued, these are all completely ad hoc procedures and are issued, these are all completely ad hoc procedures and are
accomplished by getting the human user to follow interactive natural- accomplished by getting the human user to follow interactive natural-
language instructions from the CA rather than by machine-implemented language instructions from the CA rather than by machine-implemented
published protocols. In many cases, the instructions are difficult published protocols. In many cases, the instructions are difficult
to follow and cause significant frustration and confusion. Informal to follow and cause significant frustration and confusion. Informal
usability tests by the authors indicate that webmasters often need usability tests by the authors indicate that webmasters often need
1-3 hours to obtain and install a certificate for a domain. Even in 1-3 hours to obtain and install a certificate for a domain. Even in
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presents an obstacle to the wide deployment of HTTPS and other PKIX- presents an obstacle to the wide deployment of HTTPS and other PKIX-
dependent systems because it inhibits mechanization of tasks related dependent systems because it inhibits mechanization of tasks related
to certificate issuance, deployment, and revocation. to certificate issuance, deployment, and revocation.
This document describes an extensible framework for automating the This document describes an extensible framework for automating the
issuance and domain validation procedure, thereby allowing servers issuance and domain validation procedure, thereby allowing servers
and infrastructure software to obtain certificates without user and infrastructure software to obtain certificates without user
interaction. Use of this protocol should radically simplify the interaction. Use of this protocol should radically simplify the
deployment of HTTPS and the practicality of PKIX-based authentication deployment of HTTPS and the practicality of PKIX-based authentication
for other protocols based on Transport Layer Security (TLS) for other protocols based on Transport Layer Security (TLS)
[RFC5246]. [RFC8446].
It should be noted that while the focus of this document is on It should be noted that while the focus of this document is on
validating domain names for purposes of issuing certificates in the validating domain names for purposes of issuing certificates in the
Web PKI, ACME supports extensions for uses with other identifiers in Web PKI, ACME supports extensions for uses with other identifiers in
other PKI contexts. For example, as of this writing, there is other PKI contexts. For example, as of this writing, there is
ongoing work to use ACME for issuance of Web PKI certificates ongoing work to use ACME for issuance of Web PKI certificates
attesting to IP addresses [I-D.ietf-acme-ip] and STIR certificates attesting to IP addresses [ACME-IP] and Secure Telephone Identity
attesting to telephone numbers [I-D.ietf-acme-telephone]. Revisited (STIR) certificates attesting to telephone numbers
[ACME-TELEPHONE].
ACME can also be used to automate some aspects of certificate ACME can also be used to automate some aspects of certificate
management even where non-automated processes are still needed. For management even where non-automated processes are still needed. For
example, the external account binding feature (see Section 7.3.4) can example, the external account binding feature (see Section 7.3.4) can
allow an ACME account to use authorizations that have been granted to allow an ACME account to use authorizations that have been granted to
an external, non-ACME account. This allows ACME to address issuance an external, non-ACME account. This allows ACME to address issuance
scenarios that cannot yet be fully automated, such as the issuance of scenarios that cannot yet be fully automated, such as the issuance of
Extended Validation certificates. "Extended Validation" certificates.
2. Deployment Model and Operator Experience 2. Deployment Model and Operator Experience
The guiding use case for ACME is obtaining certificates for websites The guiding use case for ACME is obtaining certificates for websites
(HTTPS [RFC2818]). In this case, a web server is intended to speak (HTTPS [RFC2818]). In this case, a web server is intended to speak
for one or more domains, and the process of certificate issuance is for one or more domains, and the process of certificate issuance is
intended to verify that this web server actually speaks for the intended to verify that this web server actually speaks for the
domain(s). domain(s).
DV certificate validation commonly checks claims about properties DV certificate validation commonly checks claims about properties
related to control of a domain name - properties that can be observed related to control of a domain name -- properties that can be
by the certificate issuer in an interactive process that can be observed by the certificate issuer in an interactive process that can
conducted purely online. That means that under typical be conducted purely online. That means that under typical
circumstances, all steps in the request, verification, and issuance circumstances, all steps in the request, verification, and issuance
process can be represented and performed by Internet protocols with process can be represented and performed by Internet protocols with
no out-of-band human intervention. no out-of-band human intervention.
Prior to ACME, when deploying an HTTPS server, a server operator Prior to ACME, when deploying an HTTPS server, a server operator
typically gets a prompt to generate a self-signed certificate. If typically gets a prompt to generate a self-signed certificate. If
the operator were instead deploying an HTTPS server using ACME, the the operator were instead deploying an HTTPS server using ACME, the
experience would be something like this: experience would be something like this:
o The operator's ACME client prompts the operator for the intended o The operator's ACME client prompts the operator for the intended
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payment information at this point. payment information at this point.
o The operator selects a CA. o The operator selects a CA.
o In the background, the ACME client contacts the CA and requests o In the background, the ACME client contacts the CA and requests
that it issue a certificate for the intended domain name(s). that it issue a certificate for the intended domain name(s).
o The CA verifies that the client controls the requested domain o The CA verifies that the client controls the requested domain
name(s) by having the ACME client perform some action(s) that can name(s) by having the ACME client perform some action(s) that can
only be done with control of the domain name(s). For example, the only be done with control of the domain name(s). For example, the
CA might require a client requesting example.com to provision DNS CA might require a client requesting example.com to provision a
record under example.com or an HTTP resource under DNS record under example.com or an HTTP resource under
http://example.com. http://example.com.
o Once the CA is satisfied, it issues the certificate and the ACME o Once the CA is satisfied, it issues the certificate and the ACME
client automatically downloads and installs it, potentially client automatically downloads and installs it, potentially
notifying the operator via email, SMS, etc. notifying the operator via email, SMS, etc.
o The ACME client periodically contacts the CA to get updated o The ACME client periodically contacts the CA to get updated
certificates, stapled OCSP responses, or whatever else would be certificates, stapled Online Certificate Status Protocol (OCSP)
required to keep the web server functional and its credentials up- responses [RFC6960], or whatever else would be required to keep
to-date. the web server functional and its credentials up to date.
In this way, it would be nearly as easy to deploy with a CA-issued In this way, it would be nearly as easy to deploy with a CA-issued
certificate as with a self-signed certificate. Furthermore, the certificate as with a self-signed certificate. Furthermore, the
maintenance of that CA-issued certificate would require minimal maintenance of that CA-issued certificate would require minimal
manual intervention. Such close integration of ACME with HTTPS manual intervention. Such close integration of ACME with HTTPS
servers allows the immediate and automated deployment of certificates servers allows the immediate and automated deployment of certificates
as they are issued, sparing the human administrator from much of the as they are issued, sparing the human administrator from much of the
time-consuming work described in the previous section. time-consuming work described in the previous section.
3. Terminology 3. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in
14 [RFC2119] [RFC8174] when, and only when, they appear in all BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
The two main roles in ACME are "client" and "server". The ACME The two main roles in ACME are "client" and "server". The ACME
client uses the protocol to request certificate management actions, client uses the protocol to request certificate management actions,
such as issuance or revocation. An ACME client may run on a web such as issuance or revocation. An ACME client may run on a web
server, mail server, or some other server system which requires valid server, mail server, or some other server system that requires valid
X.509 certificates. Or, it may run on a separate server that does X.509 certificates. Or, it may run on a separate server that does
not consume the certificate, but is authorized to respond to a CA- not consume the certificate but is authorized to respond to a CA-
provided challenge. The ACME server runs at a certification provided challenge. The ACME server runs at a certification
authority, and responds to client requests, performing the requested authority and responds to client requests, performing the requested
actions if the client is authorized. actions if the client is authorized.
An ACME client authenticates to the server by means of an "account An ACME client authenticates to the server by means of an "account
key pair". The client uses the private key of this key pair to sign key pair". The client uses the private key of this key pair to sign
all messages sent to the server. The server uses the public key to all messages sent to the server. The server uses the public key to
verify the authenticity and integrity of messages from the client. verify the authenticity and integrity of messages from the client.
4. Protocol Overview 4. Protocol Overview
ACME allows a client to request certificate management actions using ACME allows a client to request certificate management actions using
a set of JavaScript Object Notation (JSON) messages carried over a set of JavaScript Object Notation (JSON) messages [RFC8259] carried
HTTPS [RFC7159] [RFC2818]. Issuance using ACME resembles a over HTTPS [RFC2818]. Issuance using ACME resembles a traditional
traditional CA's issuance process, in which a user creates an CA's issuance process, in which a user creates an account, requests a
account, requests a certificate, and proves control of the domain(s) certificate, and proves control of the domain(s) in that certificate
in that certificate in order for the CA to issue the requested in order for the CA to issue the requested certificate.
certificate.
The first phase of ACME is for the client to request an account with The first phase of ACME is for the client to request an account with
the ACME server. The client generates an asymmetric key pair and the ACME server. The client generates an asymmetric key pair and
requests a new account, optionally providing contact information, requests a new account, optionally providing contact information,
agreeing to terms of service, and/or associating the account with an agreeing to terms of service (ToS), and/or associating the account
existing account in another system. The creation request is signed with an existing account in another system. The creation request is
with the generated private key to prove that the client controls it. signed with the generated private key to prove that the client
controls it.
Client Server Client Server
[Contact Information] [Contact Information]
[ToS Agreement] [ToS Agreement]
[Additional Data] [Additional Data]
Signature -------> Signature ------->
Account URL Account URL
<------- Account Object <------- Account Object
skipping to change at page 9, line 22 skipping to change at page 9, line 22
Signature -------> Signature ------->
<~~~~~~~~Validation~~~~~~~~> <~~~~~~~~Validation~~~~~~~~>
[CSR] [CSR]
Signature -------> Signature ------->
<------- Acknowledgement <------- Acknowledgement
<~~~~~~Await issuance~~~~~~> <~~~~~~Await issuance~~~~~~>
POST-as-GET request -------> [POST-as-GET request]
Signature ------->
<------- Certificate <------- Certificate
[] Information covered by request signatures [] Information covered by request signatures
Certificate Issuance Certificate Issuance
To revoke a certificate, the client sends a signed revocation request To revoke a certificate, the client sends a signed revocation request
indicating the certificate to be revoked: indicating the certificate to be revoked:
Client Server Client Server
skipping to change at page 9, line 47 skipping to change at page 9, line 48
<-------- Result <-------- Result
[] Information covered by request signatures [] Information covered by request signatures
Certificate Revocation Certificate Revocation
Note that while ACME is defined with enough flexibility to handle Note that while ACME is defined with enough flexibility to handle
different types of identifiers in principle, the primary use case different types of identifiers in principle, the primary use case
addressed by this document is the case where domain names are used as addressed by this document is the case where domain names are used as
identifiers. For example, all of the identifier validation identifiers. For example, all of the identifier validation
challenges described in Section 8 below address validation of domain challenges described in Section 8 address validation of domain names.
names. The use of ACME for other identifiers will require further The use of ACME for other identifiers will require further
specification in order to describe how these identifiers are encoded specification in order to describe how these identifiers are encoded
in the protocol and what types of validation challenges the server in the protocol and what types of validation challenges the server
might require. might require.
5. Character Encoding 5. Character Encoding
All requests and responses sent via HTTP by ACME clients, ACME All requests and responses sent via HTTP by ACME clients, ACME
servers, and validation servers as well as any inputs for digest servers, and validation servers as well as any inputs for digest
computations MUST be encoded using the UTF-8 [RFC3629] character set. computations MUST be encoded using the UTF-8 character set [RFC3629].
Note that identifiers that appear in certificates may have their own Note that identifiers that appear in certificates may have their own
encoding considerations (e.g., DNS names containing non-ASCII encoding considerations (e.g., DNS names containing non-ASCII
characters are expressed as A-labels rather than U-labels). Any such characters are expressed as A-labels rather than U-labels). Any such
encoding considerations are to be applied prior to the aforementioned encoding considerations are to be applied prior to the aforementioned
UTF-8 encoding. UTF-8 encoding.
6. Message Transport 6. Message Transport
Communications between an ACME client and an ACME server are done Communications between an ACME client and an ACME server are done
over HTTPS, using JSON Web Signature (JWS) [RFC7515] to provide some over HTTPS, using JSON Web Signature (JWS) [RFC7515] to provide some
additional security properties for messages sent from the client to additional security properties for messages sent from the client to
the server. HTTPS provides server authentication and the server. HTTPS provides server authentication and
confidentiality. With some ACME-specific extensions, JWS provides confidentiality. With some ACME-specific extensions, JWS provides
authentication of the client's request payloads, anti-replay authentication of the client's request payloads, anti-replay
protection, and integrity for the HTTPS request URL. protection, and integrity for the HTTPS request URL.
6.1. HTTPS Requests 6.1. HTTPS Requests
Each ACME function is accomplished by the client sending a sequence Each ACME function is accomplished by the client sending a sequence
of HTTPS requests to the server, carrying JSON messages of HTTPS requests to the server [RFC2818], carrying JSON messages
[RFC2818][RFC7159]. Use of HTTPS is REQUIRED. Each subsection of [RFC8259]. Use of HTTPS is REQUIRED. Each subsection of Section 7
Section 7 below describes the message formats used by the function below describes the message formats used by the function and the
and the order in which messages are sent. order in which messages are sent.
In most HTTPS transactions used by ACME, the ACME client is the HTTPS In most HTTPS transactions used by ACME, the ACME client is the HTTPS
client and the ACME server is the HTTPS server. The ACME server acts client and the ACME server is the HTTPS server. The ACME server acts
as a client when validating challenges: an HTTP client when as a client when validating challenges: an HTTP client when
validating an 'http-01' challenge, a DNS client with 'dns-01', etc. validating an 'http-01' challenge, a DNS client with 'dns-01', etc.
ACME servers SHOULD follow the recommendations of [RFC7525] when ACME servers SHOULD follow the recommendations of [RFC7525] when
configuring their TLS implementations. ACME servers that support TLS configuring their TLS implementations. ACME servers that support TLS
1.3 MAY allow clients to send early data (0-RTT). This is safe 1.3 MAY allow clients to send early data (0-RTT). This is safe
because the ACME protocol itself includes anti-replay protections because the ACME protocol itself includes anti-replay protections
skipping to change at page 11, line 14 skipping to change at page 11, line 14
ACME clients SHOULD send an Accept-Language header field in ACME clients SHOULD send an Accept-Language header field in
accordance with [RFC7231] to enable localization of error messages. accordance with [RFC7231] to enable localization of error messages.
ACME servers that are intended to be generally accessible need to use ACME servers that are intended to be generally accessible need to use
Cross-Origin Resource Sharing (CORS) in order to be accessible from Cross-Origin Resource Sharing (CORS) in order to be accessible from
browser-based clients [W3C.REC-cors-20140116]. Such servers SHOULD browser-based clients [W3C.REC-cors-20140116]. Such servers SHOULD
set the Access-Control-Allow-Origin header field to the value "*". set the Access-Control-Allow-Origin header field to the value "*".
Binary fields in the JSON objects used by ACME are encoded using Binary fields in the JSON objects used by ACME are encoded using
base64url encoding described in [RFC4648] Section 5, according to the base64url encoding described in Section 5 of [RFC4648] according to
profile specified in JSON Web Signature [RFC7515] Section 2. This the profile specified in JSON Web Signature in Section 2 of
encoding uses a URL safe character set. Trailing '=' characters MUST [RFC7515]. This encoding uses a URL safe character set. Trailing
be stripped. Encoded values that include trailing '=' characters '=' characters MUST be stripped. Encoded values that include
MUST be rejected as improperly encoded. trailing '=' characters MUST be rejected as improperly encoded.
6.2. Request Authentication 6.2. Request Authentication
All ACME requests with a non-empty body MUST encapsulate their All ACME requests with a non-empty body MUST encapsulate their
payload in a JSON Web Signature (JWS) [RFC7515] object, signed using payload in a JSON Web Signature (JWS) [RFC7515] object, signed using
the account's private key unless otherwise specified. The server the account's private key unless otherwise specified. The server
MUST verify the JWS before processing the request. Encapsulating MUST verify the JWS before processing the request. Encapsulating
request bodies in JWS provides authentication of requests. request bodies in JWS provides authentication of requests.
JWS objects sent in ACME requests MUST meet the following additional A JWS object sent as the body of an ACME request MUST meet the
criteria: following additional criteria:
o The JWS MUST be in the Flattened JSON Serialization [RFC7515] o The JWS MUST be in the Flattened JSON Serialization [RFC7515]
o The JWS MUST NOT have multiple signatures o The JWS MUST NOT have multiple signatures
o The JWS Unencoded Payload Option [RFC7797] MUST NOT be used o The JWS Unencoded Payload Option [RFC7797] MUST NOT be used
o The JWS Unprotected Header [RFC7515] MUST NOT be used o The JWS Unprotected Header [RFC7515] MUST NOT be used
o The JWS Payload MUST NOT be detached o The JWS Payload MUST NOT be detached
o The JWS Protected Header MUST include the following fields: o The JWS Protected Header MUST include the following fields:
* "alg" (Algorithm) * "alg" (Algorithm)
+ This field MUST NOT contain "none" or a Message + This field MUST NOT contain "none" or a Message
Authentication Code (MAC)-based algorithm (e.g. one in which Authentication Code (MAC) algorithm (e.g. one in which the
the algorithm registry description mentions MAC/HMAC). algorithm registry description mentions MAC/HMAC).
* "nonce" (defined in Section 6.5 below) * "nonce" (defined in Section 6.5)
* "url" (defined in Section 6.4 below) * "url" (defined in Section 6.4)
* Either "jwk" (JSON Web Key) or "kid" (Key ID) as specified * Either "jwk" (JSON Web Key) or "kid" (Key ID) as specified
below below
An ACME server MUST implement the "ES256" signature algorithm An ACME server MUST implement the "ES256" signature algorithm
[RFC7518] and SHOULD implement the "EdDSA" signature algorithm using [RFC7518] and SHOULD implement the "EdDSA" signature algorithm using
the "Ed25519" variant (indicated by "crv") [RFC8037]. the "Ed25519" variant (indicated by "crv") [RFC8037].
The "jwk" and "kid" fields are mutually exclusive. Servers MUST The "jwk" and "kid" fields are mutually exclusive. Servers MUST
reject requests that contain both. reject requests that contain both.
For newAccount requests, and for revokeCert requests authenticated by For newAccount requests, and for revokeCert requests authenticated by
a certificate key, there MUST be a "jwk" field. This field MUST a certificate key, there MUST be a "jwk" field. This field MUST
contain the public key corresponding to the private key used to sign contain the public key corresponding to the private key used to sign
the JWS. the JWS.
For all other requests, the request is signed using an existing For all other requests, the request is signed using an existing
account and there MUST be a "kid" field. This field MUST contain the account, and there MUST be a "kid" field. This field MUST contain
account URL received by POSTing to the newAccount resource. the account URL received by POSTing to the newAccount resource.
If the client sends a JWS signed with an algorithm that the server If the client sends a JWS signed with an algorithm that the server
does not support, then the server MUST return an error with status does not support, then the server MUST return an error with status
code 400 (Bad Request) and type code 400 (Bad Request) and type
"urn:ietf:params:acme:error:badSignatureAlgorithm". The problem "urn:ietf:params:acme:error:badSignatureAlgorithm". The problem
document returned with the error MUST include an "algorithms" field document returned with the error MUST include an "algorithms" field
with an array of supported "alg" values. See Section 6.7 for more with an array of supported "alg" values. See Section 6.7 for more
details on the structure of error responses. details on the structure of error responses.
If the server supports the signature algorithm "alg" but either does
not support or chooses to reject the public key "jwk", then the
server MUST return an error with status code 400 (Bad Request) and
type "urn:ietf:params:acme:error:badPublicKey". The problem document
detail SHOULD describe the reason for rejecting the public key; some
example reasons are:
o "alg" is "RS256" but the modulus "n" is too small (e.g., 512-bit)
o "alg" is "ES256" but "jwk" does not contain a valid P-256 public
key
o "alg" is "EdDSA" and "crv" is "Ed448", but the server only
supports "EdDSA" with "Ed25519"
o the corresponding private key is known to have been compromised
Because client requests in ACME carry JWS objects in the Flattened Because client requests in ACME carry JWS objects in the Flattened
JSON Serialization, they must have the "Content-Type" header field JSON Serialization, they must have the Content-Type header field set
set to "application/jose+json". If a request does not meet this to "application/jose+json". If a request does not meet this
requirement, then the server MUST return a response with status code requirement, then the server MUST return a response with status code
415 (Unsupported Media Type). 415 (Unsupported Media Type).
6.3. GET and POST-as-GET Requests 6.3. GET and POST-as-GET Requests
Note that authentication via signed JWS request bodies implies that Note that authentication via signed JWS request bodies implies that
requests without an entity body are not authenticated, in particular requests without an entity body are not authenticated, in particular
GET requests. Except for the cases described in this section, if the GET requests. Except for the cases described in this section, if the
server receives a GET request, it MUST return an error with status server receives a GET request, it MUST return an error with status
code 405 "Method Not Allowed" and type "malformed". code 405 (Method Not Allowed) and type "malformed".
If a client wishes to fetch a resource from the server (which would If a client wishes to fetch a resource from the server (which would
otherwise be done with a GET), then it MUST send a POST request with otherwise be done with a GET), then it MUST send a POST request with
a JWS body as described above, where the payload of the JWS is a a JWS body as described above, where the payload of the JWS is a
zero-length octet string. In other words, the "payload" field of the zero-length octet string. In other words, the "payload" field of the
JWS object MUST be present and set to the empty string (""). JWS object MUST be present and set to the empty string ("").
We will refer to these as "POST-as-GET" requests. On receiving a We will refer to these as "POST-as-GET" requests. On receiving a
request with a zero-length (and thus non-JSON) payload, the server request with a zero-length (and thus non-JSON) payload, the server
MUST authenticate the sender and verify any access control rules. MUST authenticate the sender and verify any access control rules.
skipping to change at page 13, line 23 skipping to change at page 13, line 42
these resources. This enables clients to bootstrap into the ACME these resources. This enables clients to bootstrap into the ACME
authentication system. authentication system.
6.4. Request URL Integrity 6.4. Request URL Integrity
It is common in deployment for the entity terminating TLS for HTTPS It is common in deployment for the entity terminating TLS for HTTPS
to be different from the entity operating the logical HTTPS server, to be different from the entity operating the logical HTTPS server,
with a "request routing" layer in the middle. For example, an ACME with a "request routing" layer in the middle. For example, an ACME
CA might have a content delivery network terminate TLS connections CA might have a content delivery network terminate TLS connections
from clients so that it can inspect client requests for denial-of- from clients so that it can inspect client requests for denial-of-
service protection. service (DoS) protection.
These intermediaries can also change values in the request that are These intermediaries can also change values in the request that are
not signed in the HTTPS request, e.g., the request URL and header not signed in the HTTPS request, e.g., the request URL and header
fields. ACME uses JWS to provide an integrity mechanism, which fields. ACME uses JWS to provide an integrity mechanism, which
protects against an intermediary changing the request URL to another protects against an intermediary changing the request URL to another
ACME URL. ACME URL.
As noted in Section 6.2 above, all ACME request objects carry a "url" As noted in Section 6.2, all ACME request objects carry a "url"
header parameter in their protected header. This header parameter header parameter in their protected header. This header parameter
encodes the URL to which the client is directing the request. On encodes the URL to which the client is directing the request. On
receiving such an object in an HTTP request, the server MUST compare receiving such an object in an HTTP request, the server MUST compare
the "url" header parameter to the request URL. If the two do not the "url" header parameter to the request URL. If the two do not
match, then the server MUST reject the request as unauthorized. match, then the server MUST reject the request as unauthorized.
Except for the directory resource, all ACME resources are addressed Except for the directory resource, all ACME resources are addressed
with URLs provided to the client by the server. In requests sent to with URLs provided to the client by the server. In POST requests
these resources, the client MUST set the "url" header parameter to sent to these resources, the client MUST set the "url" header
the exact string provided by the server (rather than performing any parameter to the exact string provided by the server (rather than
re-encoding on the URL). The server SHOULD perform the corresponding performing any re-encoding on the URL). The server SHOULD perform
string equality check, configuring each resource with the URL string the corresponding string equality check, configuring each resource
provided to clients and having the resource check that requests have with the URL string provided to clients and having the resource check
the same string in their "url" header parameter. The server MUST that requests have the same string in their "url" header parameter.
reject the request as unauthorized if the string equality check The server MUST reject the request as unauthorized if the string
fails. equality check fails.
6.4.1. "url" (URL) JWS Header Parameter 6.4.1. "url" (URL) JWS Header Parameter
The "url" header parameter specifies the URL [RFC3986] to which this The "url" header parameter specifies the URL [RFC3986] to which this
JWS object is directed. The "url" header parameter MUST be carried JWS object is directed. The "url" header parameter MUST be carried
in the protected header of the JWS. The value of the "url" header in the protected header of the JWS. The value of the "url" header
parameter MUST be a string representing the target URL. parameter MUST be a string representing the target URL.
6.5. Replay protection 6.5. Replay Protection
In order to protect ACME resources from any possible replay attacks, In order to protect ACME resources from any possible replay attacks,
ACME POST requests have a mandatory anti-replay mechanism. This ACME POST requests have a mandatory anti-replay mechanism. This
mechanism is based on the server maintaining a list of nonces that it mechanism is based on the server maintaining a list of nonces that it
has issued, and requiring any signed request from the client to carry has issued, and requiring any signed request from the client to carry
such a nonce. such a nonce.
An ACME server provides nonces to clients using the HTTP Replay-Nonce An ACME server provides nonces to clients using the HTTP Replay-Nonce
header field, as specified in Section 6.5.1 below. The server MUST header field, as specified in Section 6.5.1. The server MUST include
include a Replay-Nonce header field in every successful response to a a Replay-Nonce header field in every successful response to a POST
POST request and SHOULD provide it in error responses as well. request and SHOULD provide it in error responses as well.
Every JWS sent by an ACME client MUST include, in its protected Every JWS sent by an ACME client MUST include, in its protected
header, the "nonce" header parameter, with contents as defined in header, the "nonce" header parameter, with contents as defined in
Section 6.5.2 below. As part of JWS verification, the ACME server Section 6.5.2. As part of JWS verification, the ACME server MUST
MUST verify that the value of the "nonce" header is a value that the verify that the value of the "nonce" header is a value that the
server previously provided in a Replay-Nonce header field. Once a server previously provided in a Replay-Nonce header field. Once a
nonce value has appeared in an ACME request, the server MUST consider nonce value has appeared in an ACME request, the server MUST consider
it invalid, in the same way as a value it had never issued. it invalid, in the same way as a value it had never issued.
When a server rejects a request because its nonce value was When a server rejects a request because its nonce value was
unacceptable (or not present), it MUST provide HTTP status code 400 unacceptable (or not present), it MUST provide HTTP status code 400
(Bad Request), and indicate the ACME error type (Bad Request), and indicate the ACME error type
"urn:ietf:params:acme:error:badNonce". An error response with the "urn:ietf:params:acme:error:badNonce". An error response with the
"badNonce" error type MUST include a Replay-Nonce header with a fresh "badNonce" error type MUST include a Replay-Nonce header field with a
nonce that the server will accept in a retry of the original query fresh nonce that the server will accept in a retry of the original
(and possibly in other requests, according to the server's nonce query (and possibly in other requests, according to the server's
scoping policy). On receiving such a response, a client SHOULD retry nonce scoping policy). On receiving such a response, a client SHOULD
the request using the new nonce. retry the request using the new nonce.
The precise method used to generate and track nonces is up to the The precise method used to generate and track nonces is up to the
server. For example, the server could generate a random 128-bit server. For example, the server could generate a random 128-bit
value for each response, keep a list of issued nonces, and strike value for each response, keep a list of issued nonces, and strike
nonces from this list as they are used. nonces from this list as they are used.
Other than the constraint above with regard to nonces issued in Other than the constraint above with regard to nonces issued in
"badNonce" responses, ACME does not constrain how servers scope "badNonce" responses, ACME does not constrain how servers scope
nonces. Clients MAY assume that nonces have broad scope, e.g., by nonces. Clients MAY assume that nonces have broad scope, e.g., by
having a single pool of nonces used for all requests. However, when having a single pool of nonces used for all requests. However, when
retrying in response to a "badNonce" error, the client MUST use the retrying in response to a "badNonce" error, the client MUST use the
nonce provided in the error response. Servers should scope nonces nonce provided in the error response. Servers should scope nonces
broadly enough that retries are not needed very often. broadly enough that retries are not needed very often.
6.5.1. Replay-Nonce 6.5.1. Replay-Nonce
The "Replay-Nonce" header field includes a server-generated value The Replay-Nonce HTTP header field includes a server-generated value
that the server can use to detect unauthorized replay in future that the server can use to detect unauthorized replay in future
client requests. The server MUST generate the value provided in client requests. The server MUST generate the values provided in
Replay-Nonce in such a way that they are unique to each message, with Replay-Nonce header fields in such a way that they are unique to each
high probability, and unpredictable to anyone besides the server. message, with high probability, and unpredictable to anyone besides
For instance, it is acceptable to generate Replay-Nonces randomly. the server. For instance, it is acceptable to generate Replay-Nonces
randomly.
The value of the Replay-Nonce field MUST be an octet string encoded The value of the Replay-Nonce header field MUST be an octet string
according to the base64url encoding described in Section 2 of encoded according to the base64url encoding described in Section 2 of
[RFC7515]. Clients MUST ignore invalid Replay-Nonce values. The [RFC7515]. Clients MUST ignore invalid Replay-Nonce values. The
ABNF [RFC5234] for the Replay-Nonce header field follows: ABNF [RFC5234] for the Replay-Nonce header field follows:
base64url = ALPHA / DIGIT / "-" / "_" base64url = ALPHA / DIGIT / "-" / "_"
Replay-Nonce = 1*base64url Replay-Nonce = 1*base64url
The Replay-Nonce header field SHOULD NOT be included in HTTP request The Replay-Nonce header field SHOULD NOT be included in HTTP request
messages. messages.
skipping to change at page 15, line 46 skipping to change at page 16, line 23
[RFC7515]. If the value of a "nonce" header parameter is not valid [RFC7515]. If the value of a "nonce" header parameter is not valid
according to this encoding, then the verifier MUST reject the JWS as according to this encoding, then the verifier MUST reject the JWS as
malformed. malformed.
6.6. Rate Limits 6.6. Rate Limits
Creation of resources can be rate limited by ACME servers to ensure Creation of resources can be rate limited by ACME servers to ensure
fair usage and prevent abuse. Once the rate limit is exceeded, the fair usage and prevent abuse. Once the rate limit is exceeded, the
server MUST respond with an error with the type server MUST respond with an error with the type
"urn:ietf:params:acme:error:rateLimited". Additionally, the server "urn:ietf:params:acme:error:rateLimited". Additionally, the server
SHOULD send a "Retry-After" header [RFC7231] indicating when the SHOULD send a Retry-After header field [RFC7231] indicating when the
current request may succeed again. If multiple rate limits are in current request may succeed again. If multiple rate limits are in
place, that is the time where all rate limits allow access again for place, that is the time where all rate limits allow access again for
the current request with exactly the same parameters. the current request with exactly the same parameters.
In addition to the human-readable "detail" field of the error In addition to the human-readable "detail" field of the error
response, the server MAY send one or multiple link relations in the response, the server MAY send one or multiple link relations in the
"Link" header [RFC8288] pointing to documentation about the specific Link header field [RFC8288] pointing to documentation about the
rate limit that was hit, using the "help" link relation type. specific rate limit that was hit, using the "help" link relation
type.
6.7. Errors 6.7. Errors
Errors can be reported in ACME both at the HTTP layer and within Errors can be reported in ACME both at the HTTP layer and within
challenge objects as defined in Section 8. ACME servers can return challenge objects as defined in Section 8. ACME servers can return
responses with an HTTP error response code (4XX or 5XX). For responses with an HTTP error response code (4XX or 5XX). For
example: If the client submits a request using a method not allowed example, if the client submits a request using a method not allowed
in this document, then the server MAY return status code 405 (Method in this document, then the server MAY return status code 405 (Method
Not Allowed). Not Allowed).
When the server responds with an error status, it SHOULD provide When the server responds with an error status, it SHOULD provide
additional information using a problem document [RFC7807]. To additional information using a problem document [RFC7807]. To
facilitate automatic response to errors, this document defines the facilitate automatic response to errors, this document defines the
following standard tokens for use in the "type" field (within the following standard tokens for use in the "type" field (within the
ACME URN namespace "urn:ietf:params:acme:error:"): ACME URN namespace "urn:ietf:params:acme:error:"):
+-------------------------+-----------------------------------------+ +-------------------------+-----------------------------------------+
skipping to change at page 16, line 41 skipping to change at page 17, line 21
| alreadyRevoked | The request specified a certificate to | | alreadyRevoked | The request specified a certificate to |
| | be revoked that has already been | | | be revoked that has already been |
| | revoked | | | revoked |
| | | | | |
| badCSR | The CSR is unacceptable (e.g., due to a | | badCSR | The CSR is unacceptable (e.g., due to a |
| | short key) | | | short key) |
| | | | | |
| badNonce | The client sent an unacceptable anti- | | badNonce | The client sent an unacceptable anti- |
| | replay nonce | | | replay nonce |
| | | | | |
| badPublicKey | The JWS was signed by a public key the |
| | server does not support |
| | |
| badRevocationReason | The revocation reason provided is not | | badRevocationReason | The revocation reason provided is not |
| | allowed by the server | | | allowed by the server |
| | | | | |
| badSignatureAlgorithm | The JWS was signed with an algorithm | | badSignatureAlgorithm | The JWS was signed with an algorithm |
| | the server does not support | | | the server does not support |
| | | | | |
| caa | Certification Authority Authorization | | caa | Certification Authority Authorization |
| | (CAA) records forbid the CA from | | | (CAA) records forbid the CA from |
| | issuing | | | issuing a certificate |
| | | | | |
| compound | Specific error conditions are indicated | | compound | Specific error conditions are indicated |
| | in the "subproblems" array. | | | in the "subproblems" array |
| | | | | |
| connection | The server could not connect to | | connection | The server could not connect to |
| | validation target | | | validation target |
| | | | | |
| dns | There was a problem with a DNS query | | dns | There was a problem with a DNS query |
| | during identifier validation | | | during identifier validation |
| | | | | |
| externalAccountRequired | The request must include a value for | | externalAccountRequired | The request must include a value for |
| | the "externalAccountBinding" field | | | the "externalAccountBinding" field |
| | | | | |
| incorrectResponse | Response received didn't match the | | incorrectResponse | Response received didn't match the |
| | challenge's requirements | | | challenge's requirements |
| | | | | |
| invalidContact | A contact URL for an account was | | invalidContact | A contact URL for an account was |
| | invalid | | | invalid |
| | | | | |
| malformed | The request message was malformed | | malformed | The request message was malformed |
| | | | | |
| orderNotReady | The request attempted to finalize an |
| | order that is not ready to be finalized |
| | |
| rateLimited | The request exceeds a rate limit | | rateLimited | The request exceeds a rate limit |
| | | | | |
| rejectedIdentifier | The server will not issue for the | | rejectedIdentifier | The server will not issue certificates |
| | identifier | | | for the identifier |
| | | | | |
| serverInternal | The server experienced an internal | | serverInternal | The server experienced an internal |
| | error | | | error |
| | | | | |
| tls | The server received a TLS error during | | tls | The server received a TLS error during |
| | validation | | | validation |
| | | | | |
| unauthorized | The client lacks sufficient | | unauthorized | The client lacks sufficient |
| | authorization | | | authorization |
| | | | | |
skipping to change at page 18, line 14 skipping to change at page 18, line 46
In the remainder of this document, we use the tokens in the table In the remainder of this document, we use the tokens in the table
above to refer to error types, rather than the full URNs. For above to refer to error types, rather than the full URNs. For
example, an "error of type 'badCSR'" refers to an error document with example, an "error of type 'badCSR'" refers to an error document with
"type" value "urn:ietf:params:acme:error:badCSR". "type" value "urn:ietf:params:acme:error:badCSR".
6.7.1. Subproblems 6.7.1. Subproblems
Sometimes a CA may need to return multiple errors in response to a Sometimes a CA may need to return multiple errors in response to a
request. Additionally, the CA may need to attribute errors to request. Additionally, the CA may need to attribute errors to
specific identifiers. For instance, a new-order request may contain specific identifiers. For instance, a newOrder request may contain
multiple identifiers for which the CA cannot issue. In this multiple identifiers for which the CA cannot issue certificates. In
situation, an ACME problem document MAY contain the "subproblems" this situation, an ACME problem document MAY contain the
field, containing a JSON array of problem documents, each of which "subproblems" field, containing a JSON array of problem documents,
MAY contain an "identifier" field. If present, the "identifier" each of which MAY contain an "identifier" field. If present, the
field MUST contain an ACME identifier (Section 9.7.7). The "identifier" field MUST contain an ACME identifier (Section 9.7.7).
"identifier" field MUST NOT be present at the top level in ACME
The "identifier" field MUST NOT be present at the top level in ACME
problem documents. It can only be present in subproblems. problem documents. It can only be present in subproblems.
Subproblems need not all have the same type, and do not need to match Subproblems need not all have the same type, and they do not need to
the top level type. match the top level type.
ACME clients may choose to use the "identifier" field of a subproblem ACME clients may choose to use the "identifier" field of a subproblem
as a hint that an operation would succeed if that identifier were as a hint that an operation would succeed if that identifier were
omitted. For instance, if an order contains ten DNS identifiers, and omitted. For instance, if an order contains ten DNS identifiers, and
the new-order request returns a problem document with two the newOrder request returns a problem document with two subproblems
subproblems, referencing two of those identifiers, the ACME client (referencing two of those identifiers), the ACME client may choose to
may choose to submit another order containing only the eight submit another order containing only the eight identifiers not listed
identifiers not listed in the problem document. in the problem document.
HTTP/1.1 403 Forbidden HTTP/1.1 403 Forbidden
Content-Type: application/problem+json Content-Type: application/problem+json
Link: <https://example.com/acme/directory>;rel="index"
{ {
"type": "urn:ietf:params:acme:error:malformed", "type": "urn:ietf:params:acme:error:malformed",
"detail": "Some of the identifiers requested were rejected", "detail": "Some of the identifiers requested were rejected",
"subproblems": [ "subproblems": [
{ {
"type": "urn:ietf:params:acme:error:malformed", "type": "urn:ietf:params:acme:error:malformed",
"detail": "Invalid underscore in DNS name \"_example.com\"", "detail": "Invalid underscore in DNS name \"_example.org\"",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "_example.com" "value": "_example.org"
} }
}, },
{ {
"type": "urn:ietf:params:acme:error:rejectedIdentifier", "type": "urn:ietf:params:acme:error:rejectedIdentifier",
"detail": "This CA will not issue for \"example.net\"", "detail": "This CA will not issue for \"example.net\"",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.net" "value": "example.net"
} }
} }
skipping to change at page 19, line 48 skipping to change at page 20, line 21
o Ordering a Certificate o Ordering a Certificate
o Identifier Authorization o Identifier Authorization
o Certificate Issuance o Certificate Issuance
o Certificate Revocation o Certificate Revocation
7.1. Resources 7.1. Resources
ACME is structured as a REST [REST] application with the following ACME is structured as an HTTP-based application with the following
types of resources: types of resources:
o Account resources, representing information about an account o Account resources, representing information about an account
(Section 7.1.2, Section 7.3) (Section 7.1.2, Section 7.3)
o Order resources, representing an account's requests to issue o Order resources, representing an account's requests to issue
certificates (Section 7.1.3) certificates (Section 7.1.3)
o Authorization resources, representing an account's authorization o Authorization resources, representing an account's authorization
to act for an identifier (Section 7.1.4) to act for an identifier (Section 7.1.4)
skipping to change at page 20, line 34 skipping to change at page 21, line 8
o A "revokeCert" resource (Section 7.6) o A "revokeCert" resource (Section 7.6)
o A "keyChange" resource (Section 7.3.5) o A "keyChange" resource (Section 7.3.5)
The server MUST provide "directory" and "newNonce" resources. The server MUST provide "directory" and "newNonce" resources.
ACME uses different URLs for different management functions. Each ACME uses different URLs for different management functions. Each
function is listed in a directory along with its corresponding URL, function is listed in a directory along with its corresponding URL,
so clients only need to be configured with the directory URL. These so clients only need to be configured with the directory URL. These
URLs are connected by a few different link relations [RFC5988]. URLs are connected by a few different link relations [RFC8288].
The "up" link relation is used with challenge resources to indicate The "up" link relation is used with challenge resources to indicate
the authorization resource to which a challenge belongs. It is also the authorization resource to which a challenge belongs. It is also
used, with some media types, from certificate resources to indicate a used, with some media types, from certificate resources to indicate a
resource from which the client may fetch a chain of CA certificates resource from which the client may fetch a chain of CA certificates
that could be used to validate the certificate in the original that could be used to validate the certificate in the original
resource. resource.
The "index" link relation is present on all resources other than the The "index" link relation is present on all resources other than the
directory and indicates the URL of the directory. directory and indicates the URL of the directory.
skipping to change at page 21, line 33 skipping to change at page 22, line 9
| | "up" | | "up"
V | V |
challenge challenge
ACME Resources and Relationships ACME Resources and Relationships
The following table illustrates a typical sequence of requests The following table illustrates a typical sequence of requests
required to establish a new account with the server, prove control of required to establish a new account with the server, prove control of
an identifier, issue a certificate, and fetch an updated certificate an identifier, issue a certificate, and fetch an updated certificate
some time after issuance. The "->" is a mnemonic for a Location some time after issuance. The "->" is a mnemonic for a Location
header pointing to a created resource. header field pointing to a created resource.
+-------------------+--------------------------------+--------------+ +-------------------+--------------------------------+--------------+
| Action | Request | Response | | Action | Request | Response |
+-------------------+--------------------------------+--------------+ +-------------------+--------------------------------+--------------+
| Get directory | GET directory | 200 | | Get directory | GET directory | 200 |
| | | | | | | |
| Get nonce | HEAD newNonce | 200 | | Get nonce | HEAD newNonce | 200 |
| | | | | | | |
| Create account | POST newAccount | 201 -> | | Create account | POST newAccount | 201 -> |
| | | account | | | | account |
skipping to change at page 23, line 6 skipping to change at page 23, line 14
7.1.1. Directory 7.1.1. Directory
In order to help clients configure themselves with the right URLs for In order to help clients configure themselves with the right URLs for
each ACME operation, ACME servers provide a directory object. This each ACME operation, ACME servers provide a directory object. This
should be the only URL needed to configure clients. It is a JSON should be the only URL needed to configure clients. It is a JSON
object, whose field names are drawn from the resource registry object, whose field names are drawn from the resource registry
(Section 9.7.5) and whose values are the corresponding URLs. (Section 9.7.5) and whose values are the corresponding URLs.
+------------+--------------------+ +------------+--------------------+
| Field | URL in value | | Field | URL in Value |
+------------+--------------------+ +------------+--------------------+
| newNonce | New nonce | | newNonce | New nonce |
| | | | | |
| newAccount | New account | | newAccount | New account |
| | | | | |
| newOrder | New order | | newOrder | New order |
| | | | | |
| newAuthz | New authorization | | newAuthz | New authorization |
| | | | | |
| revokeCert | Revoke certificate | | revokeCert | Revoke certificate |
| | | | | |
| keyChange | Key Change | | keyChange | Key change |
+------------+--------------------+ +------------+--------------------+
There is no constraint on the URL of the directory except that it There is no constraint on the URL of the directory except that it
should be different from the other ACME server resources' URLs, and should be different from the other ACME server resources' URLs, and
that it should not clash with other services. For instance: that it should not clash with other services. For instance:
o a host which functions as both an ACME and a Web server may want o a host that functions as both an ACME and a Web server may want to
to keep the root path "/" for an HTML "front page", and place the keep the root path "/" for an HTML "front page" and place the ACME
ACME directory under the path "/acme". directory under the path "/acme".
o a host which only functions as an ACME server could place the o a host that only functions as an ACME server could place the
directory under the path "/". directory under the path "/".
If the ACME server does not implement pre-authorization If the ACME server does not implement pre-authorization
(Section 7.4.1) it MUST omit the "newAuthz" field of the directory. (Section 7.4.1), it MUST omit the "newAuthz" field of the directory.
The object MAY additionally contain a field "meta". If present, it The object MAY additionally contain a "meta" field. If present, it
MUST be a JSON object; each field in the object is an item of MUST be a JSON object; each field in the object is an item of
metadata relating to the service provided by the ACME server. metadata relating to the service provided by the ACME server.
The following metadata items are defined (Section 9.7.6), all of The following metadata items are defined (Section 9.7.6), all of
which are OPTIONAL: which are OPTIONAL:
termsOfService (optional, string): A URL identifying the current termsOfService (optional, string): A URL identifying the current
terms of service. terms of service.
website (optional, string): An HTTP or HTTPS URL locating a website website (optional, string): An HTTP or HTTPS URL locating a website
skipping to change at page 24, line 8 skipping to change at page 24, line 17
caaIdentities (optional, array of string): The hostnames that the caaIdentities (optional, array of string): The hostnames that the
ACME server recognizes as referring to itself for the purposes of ACME server recognizes as referring to itself for the purposes of
CAA record validation as defined in [RFC6844]. Each string MUST CAA record validation as defined in [RFC6844]. Each string MUST
represent the same sequence of ASCII code points that the server represent the same sequence of ASCII code points that the server
will expect to see as the "Issuer Domain Name" in a CAA issue or will expect to see as the "Issuer Domain Name" in a CAA issue or
issuewild property tag. This allows clients to determine the issuewild property tag. This allows clients to determine the
correct issuer domain name to use when configuring CAA records. correct issuer domain name to use when configuring CAA records.
externalAccountRequired (optional, boolean): If this field is externalAccountRequired (optional, boolean): If this field is
present and set to "true", then the CA requires that all new- present and set to "true", then the CA requires that all
account requests include an "externalAccountBinding" field newAccount requests include an "externalAccountBinding" field
associating the new account with an external account. associating the new account with an external account.
Clients access the directory by sending a GET request to the Clients access the directory by sending a GET request to the
directory URL. directory URL.
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Type: application/json Content-Type: application/json
{ {
"newNonce": "https://example.com/acme/new-nonce", "newNonce": "https://example.com/acme/new-nonce",
skipping to change at page 24, line 39 skipping to change at page 24, line 48
"externalAccountRequired": false "externalAccountRequired": false
} }
} }
7.1.2. Account Objects 7.1.2. Account Objects
An ACME account resource represents a set of metadata associated with An ACME account resource represents a set of metadata associated with
an account. Account resources have the following structure: an account. Account resources have the following structure:
status (required, string): The status of this account. Possible status (required, string): The status of this account. Possible
values are: "valid", "deactivated", and "revoked". The value values are "valid", "deactivated", and "revoked". The value
"deactivated" should be used to indicate client-initiated "deactivated" should be used to indicate client-initiated
deactivation whereas "revoked" should be used to indicate server- deactivation whereas "revoked" should be used to indicate server-
initiated deactivation. (See Section 7.1.6) initiated deactivation. See Section 7.1.6.
contact (optional, array of string): An array of URLs that the contact (optional, array of string): An array of URLs that the
server can use to contact the client for issues related to this server can use to contact the client for issues related to this
account. For example, the server may wish to notify the client account. For example, the server may wish to notify the client
about server-initiated revocation or certificate expiration. For about server-initiated revocation or certificate expiration. For
information on supported URL schemes, see Section 7.3 information on supported URL schemes, see Section 7.3.
termsOfServiceAgreed (optional, boolean): Including this field in a termsOfServiceAgreed (optional, boolean): Including this field in a
new-account request, with a value of true, indicates the client's newAccount request, with a value of true, indicates the client's
agreement with the terms of service. This field is not updateable agreement with the terms of service. This field cannot be updated
by the client. by the client.
externalAccountBinding (optional, object): Including this field in a
newAccount request indicates approval by the holder of an existing
non-ACME account to bind that account to this ACME account. This
field is not updateable by the client (see Section 7.3.4).
orders (required, string): A URL from which a list of orders orders (required, string): A URL from which a list of orders
submitted by this account can be fetched via a POST-as-GET submitted by this account can be fetched via a POST-as-GET
request, as described in Section 7.1.2.1. request, as described in Section 7.1.2.1.
{ {
"status": "valid", "status": "valid",
"contact": [ "contact": [
"mailto:cert-admin@example.com", "mailto:cert-admin@example.org",
"mailto:admin@example.com" "mailto:admin@example.org"
], ],
"termsOfServiceAgreed": true, "termsOfServiceAgreed": true,
"orders": "https://example.com/acme/acct/evOfKhNU60wg/orders" "orders": "https://example.com/acme/orders/rzGoeA"
} }
7.1.2.1. Orders List 7.1.2.1. Orders List
Each account object includes an "orders" URL from which a list of Each account object includes an "orders" URL from which a list of
orders created by the account can be fetched via POST-as-GET request. orders created by the account can be fetched via POST-as-GET request.
The result of the request MUST be a JSON object whose "orders" field The result of the request MUST be a JSON object whose "orders" field
is an array of URLs, each identifying an order belonging to the is an array of URLs, each identifying an order belonging to the
account. The server SHOULD include pending orders, and SHOULD NOT account. The server SHOULD include pending orders and SHOULD NOT
include orders that are invalid in the array of URLs. The server MAY include orders that are invalid in the array of URLs. The server MAY
return an incomplete list, along with a Link header field with a return an incomplete list, along with a Link header field with a
"next" link relation indicating where further entries can be "next" link relation indicating where further entries can be
acquired. acquired.
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Type: application/json Content-Type: application/json
Link: <https://example.com/acme/acct/evOfKhNU60wg/orders?cursor=2>;rel="next" Link: <https://example.com/acme/directory>;rel="index"
Link: <https://example.com/acme/orders/rzGoeA?cursor=2>;rel="next"
{ {
"orders": [ "orders": [
"https://example.com/acme/order/TOlocE8rfgo", "https://example.com/acme/order/TOlocE8rfgo",
"https://example.com/acme/order/4E16bbL5iSw", "https://example.com/acme/order/4E16bbL5iSw",
/* more URLs not shown for example brevity */ /* more URLs not shown for example brevity */
"https://example.com/acme/order/neBHYLfw0mg" "https://example.com/acme/order/neBHYLfw0mg"
] ]
} }
7.1.3. Order Objects 7.1.3. Order Objects
An ACME order object represents a client's request for a certificate An ACME order object represents a client's request for a certificate
and is used to track the progress of that order through to issuance. and is used to track the progress of that order through to issuance.
Thus, the object contains information about the requested Thus, the object contains information about the requested
certificate, the authorizations that the server requires the client certificate, the authorizations that the server requires the client
to complete, and any certificates that have resulted from this order. to complete, and any certificates that have resulted from this order.
status (required, string): The status of this order. Possible status (required, string): The status of this order. Possible
values are: "pending", "ready", "processing", "valid", and values are "pending", "ready", "processing", "valid", and
"invalid". (See Section 7.1.6) "invalid". See Section 7.1.6.
expires (optional, string): The timestamp after which the server expires (optional, string): The timestamp after which the server
will consider this order invalid, encoded in the format specified will consider this order invalid, encoded in the format specified
in RFC 3339 [RFC3339]. This field is REQUIRED for objects with in [RFC3339]. This field is REQUIRED for objects with "pending"
"pending" or "valid" in the status field. or "valid" in the status field.
identifiers (required, array of object): An array of identifier identifiers (required, array of object): An array of identifier
objects that the order pertains to. objects that the order pertains to.
type (required, string): The type of identifier. This document type (required, string): The type of identifier. This document
defines the "dns" identifier type. See the registry defined in defines the "dns" identifier type. See the registry defined in
Section 9.7.7 for any others. Section 9.7.7 for any others.
value (required, string): The identifier itself. value (required, string): The identifier itself.
skipping to change at page 26, line 40 skipping to change at page 27, line 14
error (optional, object): The error that occurred while processing error (optional, object): The error that occurred while processing
the order, if any. This field is structured as a problem document the order, if any. This field is structured as a problem document
[RFC7807]. [RFC7807].
authorizations (required, array of string): For pending orders, the authorizations (required, array of string): For pending orders, the
authorizations that the client needs to complete before the authorizations that the client needs to complete before the
requested certificate can be issued (see Section 7.5), including requested certificate can be issued (see Section 7.5), including
unexpired authorizations that the client has completed in the past unexpired authorizations that the client has completed in the past
for identifiers specified in the order. The authorizations for identifiers specified in the order. The authorizations
required are dictated by server policy and there may not be a 1:1 required are dictated by server policy; there may not be a 1:1
relationship between the order identifiers and the authorizations relationship between the order identifiers and the authorizations
required. For final orders (in the "valid" or "invalid" state), required. For final orders (in the "valid" or "invalid" state),
the authorizations that were completed. Each entry is a URL from the authorizations that were completed. Each entry is a URL from
which an authorization can be fetched with a POST-as-GET request. which an authorization can be fetched with a POST-as-GET request.
finalize (required, string): A URL that a CSR must be POSTed to once finalize (required, string): A URL that a CSR must be POSTed to once
all of the order's authorizations are satisfied to finalize the all of the order's authorizations are satisfied to finalize the
order. The result of a successful finalization will be the order. The result of a successful finalization will be the
population of the certificate URL for the order. population of the certificate URL for the order.
certificate (optional, string): A URL for the certificate that has certificate (optional, string): A URL for the certificate that has
been issued in response to this order. been issued in response to this order.
{ {
"status": "valid", "status": "valid",
"expires": "2015-03-01T14:09:07.99Z", "expires": "2016-01-20T14:09:07.99Z",
"identifiers": [ "identifiers": [
{ "type": "dns", "value": "example.com" }, { "type": "dns", "value": "www.example.org" },
{ "type": "dns", "value": "www.example.com" } { "type": "dns", "value": "example.org" }
], ],
"notBefore": "2016-01-01T00:00:00Z", "notBefore": "2016-01-01T00:00:00Z",
"notAfter": "2016-01-08T00:00:00Z", "notAfter": "2016-01-08T00:00:00Z",
"authorizations": [ "authorizations": [
"https://example.com/acme/authz/PAniVnsZcis", "https://example.com/acme/authz/PAniVnsZcis",
"https://example.com/acme/authz/r4HqLzrSrpI" "https://example.com/acme/authz/r4HqLzrSrpI"
], ],
"finalize": "https://example.com/acme/order/TOlocE8rfgo/finalize", "finalize": "https://example.com/acme/order/TOlocE8rfgo/finalize",
"certificate": "https://example.com/acme/cert/jWCdfHVGY2M" "certificate": "https://example.com/acme/cert/mAt3xBGaobw"
} }
Any identifier of type "dns" in a new-order request MAY have a Any identifier of type "dns" in a newOrder request MAY have a
wildcard domain name as its value. A wildcard domain name consists wildcard domain name as its value. A wildcard domain name consists
of a single asterisk character followed by a single full stop of a single asterisk character followed by a single full stop
character ("*.") followed by a domain name as defined for use in the character ("*.") followed by a domain name as defined for use in the
Subject Alternate Name Extension by RFC 5280 [RFC5280]. An Subject Alternate Name Extension by [RFC5280]. An authorization
authorization returned by the server for a wildcard domain name returned by the server for a wildcard domain name identifier MUST NOT
identifier MUST NOT include the asterisk and full stop ("*.") prefix include the asterisk and full stop ("*.") prefix in the authorization
in the authorization identifier value. The returned authorization identifier value. The returned authorization MUST include the
MUST include the optional "wildcard" field, with a value of true. optional "wildcard" field, with a value of true.
The elements of the "authorizations" and "identifiers" array are The elements of the "authorizations" and "identifiers" arrays are
immutable once set. The server MUST NOT change the contents of immutable once set. The server MUST NOT change the contents of
either array after they are created. If a client observes a change either array after they are created. If a client observes a change
in the contents of either array, then it SHOULD consider the order in the contents of either array, then it SHOULD consider the order
invalid. invalid.
The "authorizations" array of the order SHOULD reflect all The "authorizations" array of the order SHOULD reflect all
authorizations that the CA takes into account in deciding to issue, authorizations that the CA takes into account in deciding to issue,
even if some authorizations were fulfilled in earlier orders or in even if some authorizations were fulfilled in earlier orders or in
pre-authorization transactions. For example, if a CA allows multiple pre-authorization transactions. For example, if a CA allows multiple
orders to be fulfilled based on a single authorization transaction, orders to be fulfilled based on a single authorization transaction,
skipping to change at page 28, line 33 skipping to change at page 29, line 8
An ACME authorization object represents a server's authorization for An ACME authorization object represents a server's authorization for
an account to represent an identifier. In addition to the an account to represent an identifier. In addition to the
identifier, an authorization includes several metadata fields, such identifier, an authorization includes several metadata fields, such
as the status of the authorization (e.g., "pending", "valid", or as the status of the authorization (e.g., "pending", "valid", or
"revoked") and which challenges were used to validate possession of "revoked") and which challenges were used to validate possession of
the identifier. the identifier.
The structure of an ACME authorization resource is as follows: The structure of an ACME authorization resource is as follows:
identifier (required, object): The identifier that the account is identifier (required, object): The identifier that the account is
authorized to represent authorized to represent.
type (required, string): The type of identifier. (See below and type (required, string): The type of identifier (see below and
Section 9.7.7) Section 9.7.7).
value (required, string): The identifier itself. value (required, string): The identifier itself.
status (required, string): The status of this authorization. status (required, string): The status of this authorization.
Possible values are: "pending", "valid", "invalid", "deactivated", Possible values are "pending", "valid", "invalid", "deactivated",
"expired", and "revoked". (See Section 7.1.6) "expired", and "revoked". See Section 7.1.6.
expires (optional, string): The timestamp after which the server expires (optional, string): The timestamp after which the server
will consider this authorization invalid, encoded in the format will consider this authorization invalid, encoded in the format
specified in RFC 3339 [RFC3339]. This field is REQUIRED for specified in [RFC3339]. This field is REQUIRED for objects with
objects with "valid" in the "status" field. "valid" in the "status" field.
challenges (required, array of objects): For pending authorizations, challenges (required, array of objects): For pending authorizations,
the challenges that the client can fulfill in order to prove the challenges that the client can fulfill in order to prove
possession of the identifier. For valid authorizations, the possession of the identifier. For valid authorizations, the
challenge that was validated. For invalid authorizations, the challenge that was validated. For invalid authorizations, the
challenge that was attempted and failed. Each array entry is an challenge that was attempted and failed. Each array entry is an
object with parameters required to validate the challenge. A object with parameters required to validate the challenge. A
client should attempt to fulfill one of these challenges, and a client should attempt to fulfill one of these challenges, and a
server should consider any one of the challenges sufficient to server should consider any one of the challenges sufficient to
make the authorization valid. make the authorization valid.
wildcard (optional, boolean): For authorizations created as a result wildcard (optional, boolean): This field MUST be present and true
of a newOrder request containing a DNS identifier with a value for authorizations created as a result of a newOrder request
that contained a wildcard prefix this field MUST be present, and containing a DNS identifier with a value that was a wildcard
true. domain name. For other authorizations, it MUST be absent.
Wildcard domain names are described in Section 7.1.3.
The only type of identifier defined by this specification is a fully- The only type of identifier defined by this specification is a fully
qualified domain name (type: "dns"). The domain name MUST be encoded qualified domain name (type: "dns"). The domain name MUST be encoded
in the form in which it would appear in a certificate. That is, it in the form in which it would appear in a certificate. That is, it
MUST be encoded according to the rules in Section 7 of [RFC5280]. MUST be encoded according to the rules in Section 7 of [RFC5280].
Servers MUST verify any identifier values that begin with the ASCII Servers MUST verify any identifier values that begin with the ASCII-
Compatible Encoding prefix "xn--" as defined in [RFC5890] are Compatible Encoding prefix "xn--" as defined in [RFC5890] are
properly encoded. Wildcard domain names (with "*" as the first properly encoded. Wildcard domain names (with "*" as the first
label) MUST NOT be included in authorization objects. If an label) MUST NOT be included in authorization objects. If an
authorization object conveys authorization for the base domain of a authorization object conveys authorization for the base domain of a
newOrder DNS type identifier with a wildcard prefix then the optional newOrder DNS identifier containing a wildcard domain name, then the
authorizations "wildcard" field MUST be present with a value of true. optional authorizations "wildcard" field MUST be present with a value
of true.
Section 8 describes a set of challenges for domain name validation. Section 8 describes a set of challenges for domain name validation.
{ {
"status": "valid", "status": "valid",
"expires": "2015-03-01T14:09:07.99Z", "expires": "2015-03-01T14:09:07.99Z",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.org" "value": "www.example.org"
}, },
"challenges": [ "challenges": [
{ {
"url": "https://example.com/acme/chall/prV_B7yEyA4", "url": "https://example.com/acme/chall/prV_B7yEyA4",
"type": "http-01", "type": "http-01",
"status": "valid", "status": "valid",
"token": "DGyRejmCefe7v4NfDGDKfA", "token": "DGyRejmCefe7v4NfDGDKfA",
"validated": "2014-12-01T12:05:58.16Z" "validated": "2014-12-01T12:05:58.16Z"
} }
skipping to change at page 31, line 8 skipping to change at page 31, line 34
valid invalid valid invalid
State Transitions for Challenge Objects State Transitions for Challenge Objects
Authorization objects are created in the "pending" state. If one of Authorization objects are created in the "pending" state. If one of
the challenges listed in the authorization transitions to the "valid" the challenges listed in the authorization transitions to the "valid"
state, then the authorization also changes to the "valid" state. If state, then the authorization also changes to the "valid" state. If
the client attempts to fulfill a challenge and fails, or if there is the client attempts to fulfill a challenge and fails, or if there is
an error while the authorization is still pending, then the an error while the authorization is still pending, then the
authorization transitions to the "invalid" state. Once the authorization transitions to the "invalid" state. Once the
authorization is in the valid state, it can expire ("expired"), be authorization is in the "valid" state, it can expire ("expired"), be
deactivated by the client ("deactivated", see Section 7.5.2), or deactivated by the client ("deactivated", see Section 7.5.2), or
revoked by the server ("revoked"). revoked by the server ("revoked").
pending --------------------+ pending --------------------+
| | | |
Challenge failure | | Challenge failure | |
or | | or | |
Error | Challenge valid | Error | Challenge valid |
+---------+---------+ | +---------+---------+ |
| | | | | |
skipping to change at page 31, line 42 skipping to change at page 32, line 35
State Transitions for Authorization Objects State Transitions for Authorization Objects
Order objects are created in the "pending" state. Once all of the Order objects are created in the "pending" state. Once all of the
authorizations listed in the order object are in the "valid" state, authorizations listed in the order object are in the "valid" state,
the order transitions to the "ready" state. The order moves to the the order transitions to the "ready" state. The order moves to the
"processing" state after the client submits a request to the order's "processing" state after the client submits a request to the order's
"finalize" URL and the CA begins the issuance process for the "finalize" URL and the CA begins the issuance process for the
certificate. Once the certificate is issued, the order enters the certificate. Once the certificate is issued, the order enters the
"valid" state. If an error occurs at any of these stages, the order "valid" state. If an error occurs at any of these stages, the order
moves to the "invalid" state. The order also moves to the "invalid" moves to the "invalid" state. The order also moves to the "invalid"
state if it expires, or one of its authorizations enters a final state if it expires or one of its authorizations enters a final state
state other than "valid" ("expired", "revoked", "deactivated"). other than "valid" ("expired", "revoked", or "deactivated").
pending --------------+ pending --------------+
| | | |
| All authz | | All authz |
| "valid" | | "valid" |
V | V |
ready ---------------+ ready ---------------+
| | | |
| Receive | | Receive |
| finalize | | finalize |
skipping to change at page 33, line 7 skipping to change at page 34, line 14
7.2. Getting a Nonce 7.2. Getting a Nonce
Before sending a POST request to the server, an ACME client needs to Before sending a POST request to the server, an ACME client needs to
have a fresh anti-replay nonce to put in the "nonce" header of the have a fresh anti-replay nonce to put in the "nonce" header of the
JWS. In most cases, the client will have gotten a nonce from a JWS. In most cases, the client will have gotten a nonce from a
previous request. However, the client might sometimes need to get a previous request. However, the client might sometimes need to get a
new nonce, e.g., on its first request to the server or if an existing new nonce, e.g., on its first request to the server or if an existing
nonce is no longer valid. nonce is no longer valid.
To get a fresh nonce, the client sends a HEAD request to the new- To get a fresh nonce, the client sends a HEAD request to the newNonce
nonce resource on the server. The server's response MUST include a resource on the server. The server's response MUST include a Replay-
Replay-Nonce header field containing a fresh nonce, and SHOULD have Nonce header field containing a fresh nonce and SHOULD have status
status code 200 (OK). The server MUST also respond to GET requests code 200 (OK). The server MUST also respond to GET requests for this
for this resource, returning an empty body (while still providing a resource, returning an empty body (while still providing a Replay-
Replay-Nonce header) with a 204 (No Content) status. Nonce header) with a status code of 204 (No Content).
HEAD /acme/new-nonce HTTP/1.1 HEAD /acme/new-nonce HTTP/1.1
Host: example.com Host: example.com
HTTP/1.1 200 OK HTTP/1.1 200 OK
Replay-Nonce: oFvnlFP1wIhRlYS2jTaXbA Replay-Nonce: oFvnlFP1wIhRlYS2jTaXbA
Cache-Control: no-store Cache-Control: no-store
Link: <https://example.com/acme/directory>;rel="index"
Proxy caching of responses from the new-nonce resource can cause Proxy caching of responses from the newNonce resource can cause
clients receive the same nonce repeatedly, leading to badNonce clients to receive the same nonce repeatedly, leading to "badNonce"
errors. The server MUST include a Cache-Control header field with errors. The server MUST include a Cache-Control header field with
the "no-store" directive in responses for the new-nonce resource, in the "no-store" directive in responses for the newNonce resource, in
order to prevent caching of this resource. order to prevent caching of this resource.
7.3. Account Management 7.3. Account Management
In this section, we describe how an ACME client can create an account In this section, we describe how an ACME client can create an account
on an ACME server, and perform some modifications to the account on an ACME server and perform some modifications to the account after
after it has been created. it has been created.
A client creates a new account with the server by sending a POST A client creates a new account with the server by sending a POST
request to the server's new-account URL. The body of the request is request to the server's newAccount URL. The body of the request is a
a stub account object containing some subset of the following fields: stub account object containing some subset of the following fields:
contact (optional, array of string): Same meaning as the contact (optional, array of string): Same meaning as the
corresponding server field defined in Section 7.1.2 corresponding server field defined in Section 7.1.2.
termsOfServiceAgreed (optional, boolean): Same meaning as the termsOfServiceAgreed (optional, boolean): Same meaning as the
corresponding server field defined in Section 7.1.2 corresponding server field defined in Section 7.1.2.
onlyReturnExisting (optional, boolean): If this field is present onlyReturnExisting (optional, boolean): If this field is present
with the value "true", then the server MUST NOT create a new with the value "true", then the server MUST NOT create a new
account if one does not already exist. This allows a client to account if one does not already exist. This allows a client to
look up an account URL based on an account key (see look up an account URL based on an account key (see
Section 7.3.1). Section 7.3.1).
externalAccountBinding (optional, object): An optional field for externalAccountBinding (optional, object): Same meaning as the
binding the new account with an existing non-ACME account (see corresponding server field defined in Section 7.1.2
Section 7.3.4).
POST /acme/new-account HTTP/1.1 POST /acme/new-account HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"jwk": {...}, "jwk": {...},
"nonce": "6S8IqOGY7eL2lsGoTZYifg", "nonce": "6S8IqOGY7eL2lsGoTZYifg",
"url": "https://example.com/acme/new-account" "url": "https://example.com/acme/new-account"
}), }),
"payload": base64url({ "payload": base64url({
"termsOfServiceAgreed": true, "termsOfServiceAgreed": true,
"contact": [ "contact": [
"mailto:cert-admin@example.com", "mailto:cert-admin@example.org",
"mailto:admin@example.com" "mailto:admin@example.org"
] ]
}), }),
"signature": "RZPOnYoPs1PhjszF...-nh6X1qtOFPB519I" "signature": "RZPOnYoPs1PhjszF...-nh6X1qtOFPB519I"
} }
The server MUST ignore any values provided in the "orders" fields in The server MUST ignore any values provided in the "orders" fields in
account bodies sent by the client, as well as any other fields that account objects sent by the client, as well as any other fields that
it does not recognize. If new fields are specified in the future, it does not recognize. If new fields are specified in the future,
the specification of those fields MUST describe whether they can be the specification of those fields MUST describe whether they can be
provided by the client. provided by the client. The server MUST NOT reflect the
"onlyReturnExisting" field or any unrecognized fields in the
In general, the server MUST ignore any fields in the request object resulting account object. This allows clients to detect when servers
that it does not recognize. In particular, it MUST NOT reflect do not support an extension field.
unrecognized fields in the resulting account object. This allows
clients to detect when servers do not support an extension field.
The server SHOULD validate that the contact URLs in the "contact" The server SHOULD validate that the contact URLs in the "contact"
field are valid and supported by the server. If the server validates field are valid and supported by the server. If the server validates
contact URLs it MUST support the "mailto" scheme. Clients MUST NOT contact URLs, it MUST support the "mailto" scheme. Clients MUST NOT
provide a "mailto" URL in the "contact" field that contains "hfields" provide a "mailto" URL in the "contact" field that contains "hfields"
[RFC6068], or more than one "addr-spec" in the "to" component. If a [RFC6068] or more than one "addr-spec" in the "to" component. If a
server encounters a "mailto" contact URL that does not meet these server encounters a "mailto" contact URL that does not meet these
criteria, then it SHOULD reject it as invalid. criteria, then it SHOULD reject it as invalid.
If the server rejects a contact URL for using an unsupported scheme If the server rejects a contact URL for using an unsupported scheme,
it MUST return an error of type "unsupportedContact", with a it MUST return an error of type "unsupportedContact", with a
description describing the error and what types of contact URLs the description of the error and what types of contact URLs the server
server considers acceptable. If the server rejects a contact URL for considers acceptable. If the server rejects a contact URL for using
using a supported scheme but an invalid value then the server MUST a supported scheme but an invalid value, then the server MUST return
return an error of type "invalidContact". an error of type "invalidContact".
If the server wishes to require the client to agree to terms under If the server wishes to require the client to agree to terms under
which the ACME service is to be used, it MUST indicate the URL where which the ACME service is to be used, it MUST indicate the URL where
such terms can be accessed in the "termsOfService" subfield of the such terms can be accessed in the "termsOfService" subfield of the
"meta" field in the directory object, and the server MUST reject new- "meta" field in the directory object, and the server MUST reject
account requests that do not have the "termsOfServiceAgreed" field newAccount requests that do not have the "termsOfServiceAgreed" field
set to "true". Clients SHOULD NOT automatically agree to terms by set to "true". Clients SHOULD NOT automatically agree to terms by
default. Rather, they SHOULD require some user interaction for default. Rather, they SHOULD require some user interaction for
agreement to terms. agreement to terms.
The server creates an account and stores the public key used to The server creates an account and stores the public key used to
verify the JWS (i.e., the "jwk" element of the JWS header) to verify the JWS (i.e., the "jwk" element of the JWS header) to
authenticate future requests from the account. The server returns authenticate future requests from the account. The server returns
this account object in a 201 (Created) response, with the account URL this account object in a 201 (Created) response, with the account URL
in a Location header field. The account URL is used as the "kid" in a Location header field. The account URL is used as the "kid"
value in the JWS authenticating subsequent requests by this account value in the JWS authenticating subsequent requests by this account
(see Section 6.2). The account URL is also used for requests for (see Section 6.2). The account URL is also used for requests for
management actions on this account, as described below. management actions on this account, as described below.
HTTP/1.1 201 Created HTTP/1.1 201 Created
Content-Type: application/json Content-Type: application/json
Replay-Nonce: D8s4D2mLs8Vn-goWuPQeKA Replay-Nonce: D8s4D2mLs8Vn-goWuPQeKA
Link: <https://example.com/acme/directory>;rel="index"
Location: https://example.com/acme/acct/evOfKhNU60wg Location: https://example.com/acme/acct/evOfKhNU60wg
Link: <https://example.com/acme/some-directory>;rel="index"
{ {
"status": "valid", "status": "valid",
"contact": [ "contact": [
"mailto:cert-admin@example.com", "mailto:cert-admin@example.org",
"mailto:admin@example.com" "mailto:admin@example.org"
], ],
"orders": "https://example.com/acme/acct/evOfKhNU60wg/orders" "orders": "https://example.com/acme/acct/evOfKhNU60wg/orders"
} }
7.3.1. Finding an Account URL Given a Key 7.3.1. Finding an Account URL Given a Key
If the server receives a newAccount request signed with a key for If the server receives a newAccount request signed with a key for
which it already has an account registered with the provided account which it already has an account registered with the provided account
key, then it MUST return a response with a 200 (OK) status code and key, then it MUST return a response with status code 200 (OK) and
provide the URL of that account in the Location header field. The provide the URL of that account in the Location header field. The
body of this response represents the account object as it existed on body of this response represents the account object as it existed on
the server before this request; any fields in the request object MUST the server before this request; any fields in the request object MUST
be ignored. This allows a client that has an account key but not the be ignored. This allows a client that has an account key but not the
corresponding account URL to recover the account URL. corresponding account URL to recover the account URL.
If a client wishes to find the URL for an existing account and does If a client wishes to find the URL for an existing account and does
not want an account to be created if one does not already exist, then not want an account to be created if one does not already exist, then
it SHOULD do so by sending a POST request to the new-account URL with it SHOULD do so by sending a POST request to the newAccount URL with
a JWS whose payload has an "onlyReturnExisting" field set to "true" a JWS whose payload has an "onlyReturnExisting" field set to "true"
({"onlyReturnExisting": true}). If a client sends such a request and ({"onlyReturnExisting": true}). If a client sends such a request and
an account does not exist, then the server MUST return an error an account does not exist, then the server MUST return an error
response with status code 400 (Bad Request) and type response with status code 400 (Bad Request) and type
"urn:ietf:params:acme:error:accountDoesNotExist". "urn:ietf:params:acme:error:accountDoesNotExist".
7.3.2. Account Update 7.3.2. Account Update
If the client wishes to update this information in the future, it If the client wishes to update this information in the future, it
sends a POST request with updated information to the account URL. sends a POST request with updated information to the account URL.
skipping to change at page 36, line 38 skipping to change at page 37, line 45
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"kid": "https://example.com/acme/acct/evOfKhNU60wg", "kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "ax5RnthDqp_Yf4_HZnFLmA", "nonce": "ax5RnthDqp_Yf4_HZnFLmA",
"url": "https://example.com/acme/acct/evOfKhNU60wg" "url": "https://example.com/acme/acct/evOfKhNU60wg"
}), }),
"payload": base64url({ "payload": base64url({
"contact": [ "contact": [
"mailto:certificates@example.com", "mailto:certificates@example.org",
"mailto:admin@example.com" "mailto:admin@example.org"
] ]
}), }),
"signature": "hDXzvcj8T6fbFbmn...rDzXzzvzpRy64N0o" "signature": "hDXzvcj8T6fbFbmn...rDzXzzvzpRy64N0o"
} }
7.3.3. Changes of Terms of Service 7.3.3. Changes of Terms of Service
As described above, a client can indicate its agreement with the CA's As described above, a client can indicate its agreement with the CA's
terms of service by setting the "termsOfServiceAgreed" field in its terms of service by setting the "termsOfServiceAgreed" field in its
account object to "true". account object to "true".
skipping to change at page 37, line 20 skipping to change at page 38, line 26
include a Link header field with link relation "terms-of-service" and include a Link header field with link relation "terms-of-service" and
the latest terms-of-service URL. the latest terms-of-service URL.
The problem document returned with the error MUST also include an The problem document returned with the error MUST also include an
"instance" field, indicating a URL that the client should direct a "instance" field, indicating a URL that the client should direct a
human user to visit in order for instructions on how to agree to the human user to visit in order for instructions on how to agree to the
terms. terms.
HTTP/1.1 403 Forbidden HTTP/1.1 403 Forbidden
Replay-Nonce: T81bdZroZ2ITWSondpTmAw Replay-Nonce: T81bdZroZ2ITWSondpTmAw
Link: <https://example.com/acme/directory>;rel="index"
Link: <https://example.com/acme/terms/2017-6-02>;rel="terms-of-service" Link: <https://example.com/acme/terms/2017-6-02>;rel="terms-of-service"
Content-Type: application/problem+json Content-Type: application/problem+json
Content-Language: en Content-Language: en
{ {
"type": "urn:ietf:params:acme:error:userActionRequired", "type": "urn:ietf:params:acme:error:userActionRequired",
"detail": "Terms of service have changed", "detail": "Terms of service have changed",
"instance": "https://example.com/acme/agreement/?token=W8Ih3PswD-8" "instance": "https://example.com/acme/agreement/?token=W8Ih3PswD-8"
} }
skipping to change at page 38, line 23 skipping to change at page 39, line 33
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"jwk": /* account key */, "jwk": /* account key */,
"nonce": "K60BWPrMQG9SDxBDS_xtSw", "nonce": "K60BWPrMQG9SDxBDS_xtSw",
"url": "https://example.com/acme/new-account" "url": "https://example.com/acme/new-account"
}), }),
"payload": base64url({ "payload": base64url({
"contact": ["mailto:example@anonymous.invalid"], "contact": [
"mailto:cert-admin@example.org",
"mailto:admin@example.org"
],
"termsOfServiceAgreed": true, "termsOfServiceAgreed": true,
"externalAccountBinding": { "externalAccountBinding": {
"protected": base64url({ "protected": base64url({
"alg": "HS256", "alg": "HS256",
"kid": /* key identifier from CA */, "kid": /* key identifier from CA */,
"url": "https://example.com/acme/new-account" "url": "https://example.com/acme/new-account"
}), }),
"payload": base64url(/* same as in "jwk" above */), "payload": base64url(/* same as in "jwk" above */),
"signature": /* MAC using MAC key from CA */ "signature": /* MAC using MAC key from CA */
} }
}), }),
"signature": "5TWiqIYQfIDfALQv...x9C2mg8JGPxl5bI4" "signature": "5TWiqIYQfIDfALQv...x9C2mg8JGPxl5bI4"
} }
If such a CA requires that newAccount requests contain an
If such a CA requires that new-account requests contain an
"externalAccountBinding" field, then it MUST provide the value "true" "externalAccountBinding" field, then it MUST provide the value "true"
in the "externalAccountRequired" subfield of the "meta" field in the in the "externalAccountRequired" subfield of the "meta" field in the
directory object. If the CA receives a new-account request without directory object. If the CA receives a newAccount request without an
an "externalAccountBinding" field, then it SHOULD reply with an error "externalAccountBinding" field, then it SHOULD reply with an error of
of type "externalAccountRequired". type "externalAccountRequired".
When a CA receives a new-account request containing an When a CA receives a newAccount request containing an
"externalAccountBinding" field, it decides whether or not to verify "externalAccountBinding" field, it decides whether or not to verify
the binding. If the CA does not verify the binding, then it MUST NOT the binding. If the CA does not verify the binding, then it MUST NOT
reflect the "externalAccountBinding" field in the resulting account reflect the "externalAccountBinding" field in the resulting account
object (if any). To verify the account binding, the CA MUST take the object (if any). To verify the account binding, the CA MUST take the
following steps: following steps:
1. Verify that the value of the field is a well-formed JWS 1. Verify that the value of the field is a well-formed JWS
2. Verify that the JWS protected field meets the above criteria 2. Verify that the JWS protected field meets the above criteria
skipping to change at page 39, line 23 skipping to change at page 40, line 36
5. Verify that the payload of the JWS represents the same key as was 5. Verify that the payload of the JWS represents the same key as was
used to verify the outer JWS (i.e., the "jwk" field of the outer used to verify the outer JWS (i.e., the "jwk" field of the outer
JWS) JWS)
If all of these checks pass and the CA creates a new account, then If all of these checks pass and the CA creates a new account, then
the CA may consider the new account associated with the external the CA may consider the new account associated with the external
account corresponding to the MAC key. The account object the CA account corresponding to the MAC key. The account object the CA
returns MUST include an "externalAccountBinding" field with the same returns MUST include an "externalAccountBinding" field with the same
value as the field in the request. If any of these checks fail, then value as the field in the request. If any of these checks fail, then
the CA MUST reject the new-account request. the CA MUST reject the newAccount request.
7.3.5. Account Key Roll-over 7.3.5. Account Key Rollover
A client may wish to change the public key that is associated with an A client may wish to change the public key that is associated with an
account in order to recover from a key compromise or proactively account in order to recover from a key compromise or proactively
mitigate the impact of an unnoticed key compromise. mitigate the impact of an unnoticed key compromise.
To change the key associated with an account, the client sends a To change the key associated with an account, the client sends a
request to the server containing signatures by both the old and new request to the server containing signatures by both the old and new
keys. The signature by the new key covers the account URL and the keys. The signature by the new key covers the account URL and the
old key, signifying a request by the new key holder to take over the old key, signifying a request by the new key holder to take over the
account from the old key holder. The signature by the old key covers account from the old key holder. The signature by the old key covers
this request and its signature, and indicates the old key holder's this request and its signature, and indicates the old key holder's
assent to the roll-over request. assent to the rollover request.
To create this request object, the client first constructs a key- To create this request object, the client first constructs a
change object describing the account to be updated and its account keyChange object describing the account to be updated and its account
key: key:
account (required, string): The URL for the account being modified. account (required, string): The URL for the account being modified.
The content of this field MUST be the exact string provided in the The content of this field MUST be the exact string provided in the
Location header field in response to the new-account request that Location header field in response to the newAccount request that
created the account. created the account.
oldKey (required, JWK): The JWK representation of the old key oldKey (required, JWK): The JWK representation of the old key.
The client then encapsulates the key-change object in an "inner" JWS, The client then encapsulates the keyChange object in an "inner" JWS,
signed with the requested new account key. This "inner" JWS becomes signed with the requested new account key. This "inner" JWS becomes
the payload for the "outer" JWS that is the body of the ACME request. the payload for the "outer" JWS that is the body of the ACME request.
The outer JWS MUST meet the normal requirements for an ACME JWS (see The outer JWS MUST meet the normal requirements for an ACME JWS
Section 6.2). The inner JWS MUST meet the normal requirements, with request body (see Section 6.2). The inner JWS MUST meet the normal
the following differences: requirements, with the following differences:
o The inner JWS MUST have a "jwk" header parameter, containing the o The inner JWS MUST have a "jwk" header parameter, containing the
public key of the new key pair. public key of the new key pair.
o The inner JWS MUST have the same "url" header parameter as the o The inner JWS MUST have the same "url" header parameter as the
outer JWS. outer JWS.
o The inner JWS MUST omit the "nonce" header parameter. o The inner JWS MUST omit the "nonce" header parameter.
This transaction has signatures from both the old and new keys so This transaction has signatures from both the old and new keys so
skipping to change at page 41, line 4 skipping to change at page 42, line 30
"url": "https://example.com/acme/key-change" "url": "https://example.com/acme/key-change"
}), }),
"payload": base64url({ "payload": base64url({
"account": "https://example.com/acme/acct/evOfKhNU60wg", "account": "https://example.com/acme/acct/evOfKhNU60wg",
"oldKey": /* old key */ "oldKey": /* old key */
}), }),
"signature": "Xe8B94RD30Azj2ea...8BmZIRtcSKPSd8gU" "signature": "Xe8B94RD30Azj2ea...8BmZIRtcSKPSd8gU"
}), }),
"signature": "5TWiqIYQfIDfALQv...x9C2mg8JGPxl5bI4" "signature": "5TWiqIYQfIDfALQv...x9C2mg8JGPxl5bI4"
} }
On receiving key-change request, the server MUST perform the
On receiving a keyChange request, the server MUST perform the
following steps in addition to the typical JWS validation: following steps in addition to the typical JWS validation:
1. Validate the POST request belongs to a currently active account, 1. Validate the POST request belongs to a currently active account,
as described in Section 6. as described in Section 6.
2. Check that the payload of the JWS is a well-formed JWS object 2. Check that the payload of the JWS is a well-formed JWS object
(the "inner JWS"). (the "inner JWS").
3. Check that the JWS protected header of the inner JWS has a "jwk" 3. Check that the JWS protected header of the inner JWS has a "jwk"
field. field.
4. Check that the inner JWS verifies using the key in its "jwk" 4. Check that the inner JWS verifies using the key in its "jwk"
field. field.
5. Check that the payload of the inner JWS is a well-formed key- 5. Check that the payload of the inner JWS is a well-formed
change object (as described above). keyChange object (as described above).
6. Check that the "url" parameters of the inner and outer JWSs are 6. Check that the "url" parameters of the inner and outer JWSs are
the same. the same.
7. Check that the "account" field of the key-change object contains 7. Check that the "account" field of the keyChange object contains
the URL for the account matching the old key (i.e., the "kid" the URL for the account matching the old key (i.e., the "kid"
field in the outer JWS). field in the outer JWS).
8. Check that the "oldKey" field of the key-change object is the 8. Check that the "oldKey" field of the keyChange object is the same
same as the account key for the account in question. as the account key for the account in question.
9. Check that no account exists whose account key is the same as the 9. Check that no account exists whose account key is the same as the
key in the "jwk" header parameter of the inner JWS. key in the "jwk" header parameter of the inner JWS.
If all of these checks pass, then the server updates the If all of these checks pass, then the server updates the
corresponding account by replacing the old account key with the new corresponding account by replacing the old account key with the new
public key and returns status code 200 (OK). Otherwise, the server public key and returns status code 200 (OK). Otherwise, the server
responds with an error status code and a problem document describing responds with an error status code and a problem document describing
the error. If there is an existing account with the new key the error. If there is an existing account with the new key
provided, then the server SHOULD use status code 409 (Conflict) and provided, then the server SHOULD use status code 409 (Conflict) and
provide the URL of that account in the Location header field. provide the URL of that account in the Location header field.
Note that changing the account key for an account SHOULD NOT have any Note that changing the account key for an account SHOULD NOT have any
other impact on the account. For example, the server MUST NOT other impact on the account. For example, the server MUST NOT
invalidate pending orders or authorization transactions based on a invalidate pending orders or authorization transactions based on a
change of account key. change of account key.
7.3.6. Account Deactivation 7.3.6. Account Deactivation
A client can deactivate an account by posting a signed update to the A client can deactivate an account by posting a signed update to the
account URL with a status field of "deactivated." Clients may wish account URL with a status field of "deactivated". Clients may wish
to do this when the account key is compromised or decommissioned. A to do this when the account key is compromised or decommissioned. A
deactivated account can no longer request certificate issuance or deactivated account can no longer request certificate issuance or
access resources related to the account, such as orders or access resources related to the account, such as orders or
authorizations. If a server receives a POST or POST-as-GET from a authorizations. If a server receives a POST or POST-as-GET from a
deactivated account, it MUST return an error response with status deactivated account, it MUST return an error response with status
code 401 (Unauthorized) and type code 401 (Unauthorized) and type
"urn:ietf:params:acme:error:unauthorized". "urn:ietf:params:acme:error:unauthorized".
POST /acme/acct/evOfKhNU60wg HTTP/1.1 POST /acme/acct/evOfKhNU60wg HTTP/1.1
Host: example.com Host: example.com
skipping to change at page 43, line 8 skipping to change at page 44, line 40
response to an account deactivation, e.g., deleting data related to response to an account deactivation, e.g., deleting data related to
that account or sending mail to the account's contacts. Servers that account or sending mail to the account's contacts. Servers
SHOULD NOT revoke certificates issued by the deactivated account, SHOULD NOT revoke certificates issued by the deactivated account,
since this could cause operational disruption for servers using these since this could cause operational disruption for servers using these
certificates. ACME does not provide a way to reactivate a certificates. ACME does not provide a way to reactivate a
deactivated account. deactivated account.
7.4. Applying for Certificate Issuance 7.4. Applying for Certificate Issuance
The client begins the certificate issuance process by sending a POST The client begins the certificate issuance process by sending a POST
request to the server's new-order resource. The body of the POST is request to the server's newOrder resource. The body of the POST is a
a JWS object whose JSON payload is a subset of the order object JWS object whose JSON payload is a subset of the order object defined
defined in Section 7.1.3, containing the fields that describe the in Section 7.1.3, containing the fields that describe the certificate
certificate to be issued: to be issued:
identifiers (required, array of object): An array of identifier identifiers (required, array of object): An array of identifier
objects that the client wishes to submit an order for. objects that the client wishes to submit an order for.
type (required, string): The type of identifier. type (required, string): The type of identifier.
value (required, string): The identifier itself. value (required, string): The identifier itself.
notBefore (optional, string): The requested value of the notBefore notBefore (optional, string): The requested value of the notBefore
field in the certificate, in the date format defined in [RFC3339]. field in the certificate, in the date format defined in [RFC3339].
skipping to change at page 43, line 39 skipping to change at page 45, line 24
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"kid": "https://example.com/acme/acct/evOfKhNU60wg", "kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "5XJ1L3lEkMG7tR6pA00clA", "nonce": "5XJ1L3lEkMG7tR6pA00clA",
"url": "https://example.com/acme/new-order" "url": "https://example.com/acme/new-order"
}), }),
"payload": base64url({ "payload": base64url({
"identifiers": [ "identifiers": [
{ "type": "dns", "value": "example.com" } { "type": "dns", "value": "www.example.org" },
{ "type": "dns", "value": "example.org" }
], ],
"notBefore": "2016-01-01T00:04:00+04:00", "notBefore": "2016-01-01T00:04:00+04:00",
"notAfter": "2016-01-08T00:04:00+04:00" "notAfter": "2016-01-08T00:04:00+04:00"
}), }),
"signature": "H6ZXtGjTZyUnPeKn...wEA4TklBdh3e454g" "signature": "H6ZXtGjTZyUnPeKn...wEA4TklBdh3e454g"
} }
The server MUST return an error if it cannot fulfill the request as The server MUST return an error if it cannot fulfill the request as
specified, and MUST NOT issue a certificate with contents other than specified, and it MUST NOT issue a certificate with contents other
those requested. If the server requires the request to be modified than those requested. If the server requires the request to be
in a certain way, it should indicate the required changes using an modified in a certain way, it should indicate the required changes
appropriate error type and description. using an appropriate error type and description.
If the server is willing to issue the requested certificate, it If the server is willing to issue the requested certificate, it
responds with a 201 (Created) response. The body of this response is responds with a 201 (Created) response. The body of this response is
an order object reflecting the client's request and any an order object reflecting the client's request and any
authorizations the client must complete before the certificate will authorizations the client must complete before the certificate will
be issued. be issued.
HTTP/1.1 201 Created HTTP/1.1 201 Created
Replay-Nonce: MYAuvOpaoIiywTezizk5vw Replay-Nonce: MYAuvOpaoIiywTezizk5vw
Link: <https://example.com/acme/directory>;rel="index"
Location: https://example.com/acme/order/TOlocE8rfgo Location: https://example.com/acme/order/TOlocE8rfgo
{ {
"status": "pending", "status": "pending",
"expires": "2016-01-01T00:00:00Z", "expires": "2016-01-05T14:09:07.99Z",
"notBefore": "2016-01-01T00:00:00Z", "notBefore": "2016-01-01T00:00:00Z",
"notAfter": "2016-01-08T00:00:00Z", "notAfter": "2016-01-08T00:00:00Z",
"identifiers": [ "identifiers": [
{ "type": "dns", "value": "example.com" }, { "type": "dns", "value": "www.example.org" },
{ "type": "dns", "value": "example.org" }
], ],
"authorizations": [ "authorizations": [
"https://example.com/acme/authz/PAniVnsZcis", "https://example.com/acme/authz/PAniVnsZcis",
"https://example.com/acme/authz/r4HqLzrSrpI"
], ],
"finalize": "https://example.com/acme/order/TOlocE8rfgo/finalize" "finalize": "https://example.com/acme/order/TOlocE8rfgo/finalize"
} }
The order object returned by the server represents a promise that if The order object returned by the server represents a promise that if
the client fulfills the server's requirements before the "expires" the client fulfills the server's requirements before the "expires"
time, then the server will be willing to finalize the order upon time, then the server will be willing to finalize the order upon
request and issue the requested certificate. In the order object, request and issue the requested certificate. In the order object,
any authorization referenced in the "authorizations" array whose any authorization referenced in the "authorizations" array whose
skipping to change at page 45, line 6 skipping to change at page 47, line 13
object. object.
Once the client believes it has fulfilled the server's requirements, Once the client believes it has fulfilled the server's requirements,
it should send a POST request to the order resource's finalize URL. it should send a POST request to the order resource's finalize URL.
The POST body MUST include a CSR: The POST body MUST include a CSR:
csr (required, string): A CSR encoding the parameters for the csr (required, string): A CSR encoding the parameters for the
certificate being requested [RFC2986]. The CSR is sent in the certificate being requested [RFC2986]. The CSR is sent in the
base64url-encoded version of the DER format. (Note: Because this base64url-encoded version of the DER format. (Note: Because this
field uses base64url, and does not include headers, it is field uses base64url, and does not include headers, it is
different from PEM.). different from PEM.)
POST /acme/order/TOlocE8rfgo/finalize HTTP/1.1 POST /acme/order/TOlocE8rfgo/finalize HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"kid": "https://example.com/acme/acct/evOfKhNU60wg", "kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "MSF2j2nawWHPxxkE3ZJtKQ", "nonce": "MSF2j2nawWHPxxkE3ZJtKQ",
"url": "https://example.com/acme/order/TOlocE8rfgo/finalize" "url": "https://example.com/acme/order/TOlocE8rfgo/finalize"
}), }),
"payload": base64url({ "payload": base64url({
"csr": "MIIBPTCBxAIBADBFMQ...FS6aKdZeGsysoCo4H9P", "csr": "MIIBPTCBxAIBADBFMQ...FS6aKdZeGsysoCo4H9P",
}), }),
"signature": "uOrUfIIk5RyQ...nw62Ay1cl6AB" "signature": "uOrUfIIk5RyQ...nw62Ay1cl6AB"
} }
The CSR encodes the client's requests with regard to the content of The CSR encodes the client's requests with regard to the content of
the certificate to be issued. The CSR MUST indicate the exact same the certificate to be issued. The CSR MUST indicate the exact same
set of requested identifiers as the initial new-order request. set of requested identifiers as the initial newOrder request.
Identifiers of type "dns" MUST appear either in the commonName Identifiers of type "dns" MUST appear either in the commonName
portion of the requested subject name, or in an extensionRequest portion of the requested subject name or in an extensionRequest
attribute [RFC2985] requesting a subjectAltName extension, or both. attribute [RFC2985] requesting a subjectAltName extension, or both.
(These identifiers may appear in any sort order.) Specifications (These identifiers may appear in any sort order.) Specifications
that define new identifier types must specify where in the that define new identifier types must specify where in the
certificate signing request these identifiers can appear. certificate signing request these identifiers can appear.
A request to finalize an order will result in error if the CA is A request to finalize an order will result in an error if the CA is
unwilling to issue a certificate corresponding to the submitted CSR. unwilling to issue a certificate corresponding to the submitted CSR.
For example: For example:
o If the order indicated does not have status "ready"
o If the CSR and order identifiers differ o If the CSR and order identifiers differ
o If the account is not authorized for the identifiers indicated in o If the account is not authorized for the identifiers indicated in
the CSR the CSR
o If the CSR requests extensions that the CA is not willing to o If the CSR requests extensions that the CA is not willing to
include include
In such cases, the problem document returned by the server SHOULD use In such cases, the problem document returned by the server SHOULD use
error code "badCSR", and describe specific reasons the CSR was error code "badCSR" and describe specific reasons the CSR was
rejected in its "details" field. After returning such an error, the rejected in its "detail" field. After returning such an error, the
server SHOULD leave the order in the "ready" state, to allow the server SHOULD leave the order in the "ready" state, to allow the
client to submit a new finalize request with an amended CSR. client to submit a new finalize request with an amended CSR.
A request to finalize an order will return the order to be finalized. A request to finalize an order will result in error if the order is
The client should begin polling the order by sending a POST-as-GET not in the "ready" state. In such cases, the server MUST return a
request to the order resource to obtain its current state. The 403 (Forbidden) error with a problem document of type
status of the order will indicate what action the client should take: "orderNotReady". The client should then send a POST-as-GET request
to the order resource to obtain its current state. The status of the
order will indicate what action the client should take (see below).
If a request to finalize an order is successful, the server will
return a 200 (OK) with an updated order object. The status of the
order will indicate what action the client should take:
o "invalid": The certificate will not be issued. Consider this o "invalid": The certificate will not be issued. Consider this
order process abandoned. order process abandoned.
o "pending": The server does not believe that the client has o "pending": The server does not believe that the client has
fulfilled the requirements. Check the "authorizations" array for fulfilled the requirements. Check the "authorizations" array for
entries that are still pending. entries that are still pending.
o "ready": The server agrees that the requirements have been o "ready": The server agrees that the requirements have been
fulfilled, and is awaiting finalization. Submit a finalization fulfilled, and is awaiting finalization. Submit a finalization
request. request.
o "processing": The certificate is being issued. Send a POST-as-GET o "processing": The certificate is being issued. Send a POST-as-GET
request after the time given in the "Retry-After" header field of request after the time given in the Retry-After header field of
the response, if any. the response, if any.
o "valid": The server has issued the certificate and provisioned its o "valid": The server has issued the certificate and provisioned its
URL to the "certificate" field of the order. Download the URL to the "certificate" field of the order. Download the
certificate. certificate.
HTTP/1.1 200 OK HTTP/1.1 200 OK
Replay-Nonce: CGf81JWBsq8QyIgPCi9Q9X Replay-Nonce: CGf81JWBsq8QyIgPCi9Q9X
Link: <https://example.com/acme/directory>;rel="index"
Location: https://example.com/acme/order/TOlocE8rfgo Location: https://example.com/acme/order/TOlocE8rfgo
{ {
"status": "valid", "status": "valid",
"expires": "2015-12-31T00:17:00.00-09:00", "expires": "2016-01-20T14:09:07.99Z",
"notBefore": "2015-12-31T00:17:00.00-09:00", "notBefore": "2016-01-01T00:00:00Z",
"notAfter": "2015-12-31T00:17:00.00-09:00", "notAfter": "2016-01-08T00:00:00Z",
"identifiers": [ "identifiers": [
{ "type": "dns", "value": "example.com" }, { "type": "dns", "value": "www.example.org" },
{ "type": "dns", "value": "www.example.com" } { "type": "dns", "value": "example.org" }
], ],
"authorizations": [ "authorizations": [
"https://example.com/acme/authz/PAniVnsZcis", "https://example.com/acme/authz/PAniVnsZcis",
"https://example.com/acme/authz/r4HqLzrSrpI" "https://example.com/acme/authz/r4HqLzrSrpI"
], ],
"finalize": "https://example.com/acme/order/TOlocE8rfgo/finalize", "finalize": "https://example.com/acme/order/TOlocE8rfgo/finalize",
"certificate": "https://example.com/acme/cert/mAt3xBGaobw" "certificate": "https://example.com/acme/cert/mAt3xBGaobw"
} }
7.4.1. Pre-Authorization 7.4.1. Pre-authorization
The order process described above presumes that authorization objects The order process described above presumes that authorization objects
are created reactively, in response to a certificate order. Some are created reactively, in response to a certificate order. Some
servers may also wish to enable clients to obtain authorization for servers may also wish to enable clients to obtain authorization for
an identifier proactively, outside of the context of a specific an identifier proactively, outside of the context of a specific
issuance. For example, a client hosting virtual servers for a issuance. For example, a client hosting virtual servers for a
collection of names might wish to obtain authorization before any collection of names might wish to obtain authorization before any
virtual servers are created and only create a certificate when a virtual servers are created and only create a certificate when a
virtual server starts up. virtual server starts up.
In some cases, a CA running an ACME server might have a completely In some cases, a CA running an ACME server might have a completely
external, non-ACME process for authorizing a client to issue external, non-ACME process for authorizing a client to issue
certificates for an identifier. In these cases, the CA should certificates for an identifier. In these cases, the CA should
provision its ACME server with authorization objects corresponding to provision its ACME server with authorization objects corresponding to
these authorizations and reflect them as already valid in any orders these authorizations and reflect them as already valid in any orders
submitted by the client. submitted by the client.
If a CA wishes to allow pre-authorization within ACME, it can offer a If a CA wishes to allow pre-authorization within ACME, it can offer a
"new authorization" resource in its directory by adding the field "new authorization" resource in its directory by adding the field
"newAuthz" with a URL for the new authorization resource. "newAuthz" with a URL for the newAuthz resource.
To request authorization for an identifier, the client sends a POST To request authorization for an identifier, the client sends a POST
request to the new-authorization resource specifying the identifier request to the newAuthz resource specifying the identifier for which
for which authorization is being requested. authorization is being requested.
identifier (required, object): The identifier to appear in the identifier (required, object): The identifier to appear in the
resulting authorization object (see Section 7.1.4) resulting authorization object (see Section 7.1.4).
type (required, string): The type of identifier. type (required, string): The type of identifier.
value (required, string): The identifier itself. value (required, string): The identifier itself.
POST /acme/new-authz HTTP/1.1 POST /acme/new-authz HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"kid": "https://example.com/acme/acct/evOfKhNU60wg", "kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "uQpSjlRb4vQVCjVYAyyUWg", "nonce": "uQpSjlRb4vQVCjVYAyyUWg",
"url": "https://example.com/acme/new-authz" "url": "https://example.com/acme/new-authz"
}), }),
"payload": base64url({ "payload": base64url({
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.net" "value": "example.org"
} }
}), }),
"signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps" "signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps"
} }
Note that because the identifier in a pre-authorization request is Note that because the identifier in a pre-authorization request is
the exact identifier to be included in the authorization object, pre- the exact identifier to be included in the authorization object, pre-
authorization cannot be used to authorize issuance with wildcard DNS authorization cannot be used to authorize issuance of certificates
identifiers. containing wildcard domain names.
Before processing the authorization request, the server SHOULD Before processing the authorization request, the server SHOULD
determine whether it is willing to issue certificates for the determine whether it is willing to issue certificates for the
identifier. For example, the server should check that the identifier identifier. For example, the server should check that the identifier
is of a supported type. Servers might also check names against a is of a supported type. Servers might also check names against a
blacklist of known high-value identifiers. If the server is blacklist of known high-value identifiers. If the server is
unwilling to issue for the identifier, it SHOULD return a 403 unwilling to issue for the identifier, it SHOULD return an error with
(Forbidden) error, with a problem document describing the reason for status code 403 (Forbidden), with a problem document describing the
the rejection. reason for the rejection.
If the server is willing to proceed, it builds a pending If the server is willing to proceed, it builds a pending
authorization object from the inputs submitted by the client: authorization object from the inputs submitted by the client:
o "identifier" the identifier submitted by the client o "identifier" the identifier submitted by the client
o "status" MUST be "pending" unless the server has out-of-band o "status" MUST be "pending" unless the server has out-of-band
information about the client's authorization status information about the client's authorization status
o "challenges" as selected by the server's policy for this o "challenges" as selected by the server's policy for this
identifier identifier
The server allocates a new URL for this authorization, and returns a The server allocates a new URL for this authorization and returns a
201 (Created) response, with the authorization URL in the Location 201 (Created) response with the authorization URL in the Location
header field, and the JSON authorization object in the body. The header field and the JSON authorization object in the body. The
client then follows the process described in Section 7.5 to complete client then follows the process described in Section 7.5 to complete
the authorization process. the authorization process.
7.4.2. Downloading the Certificate 7.4.2. Downloading the Certificate
To download the issued certificate, the client simply sends a POST- To download the issued certificate, the client simply sends a POST-
as-GET request to the certificate URL. as-GET request to the certificate URL.
The default format of the certificate is application/pem-certificate- The default format of the certificate is application/pem-certificate-
chain (see Section 9). chain (see Section 9).
The server MAY provide one or more link relation header fields The server MAY provide one or more link relation header fields
[RFC5988] with relation "alternate". Each such field SHOULD express [RFC8288] with relation "alternate". Each such field SHOULD express
an alternative certificate chain starting with the same end-entity an alternative certificate chain starting with the same end-entity
certificate. This can be used to express paths to various trust certificate. This can be used to express paths to various trust
anchors. Clients can fetch these alternates and use their own anchors. Clients can fetch these alternates and use their own
heuristics to decide which is optimal. heuristics to decide which is optimal.
POST /acme/cert/mAt3xBGaobw HTTP/1.1 POST /acme/cert/mAt3xBGaobw HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
Accept: application/pem-certificate-chain Accept: application/pem-certificate-chain
skipping to change at page 50, line 23 skipping to change at page 52, line 23
"kid": "https://example.com/acme/acct/evOfKhNU60wg", "kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "uQpSjlRb4vQVCjVYAyyUWg", "nonce": "uQpSjlRb4vQVCjVYAyyUWg",
"url": "https://example.com/acme/cert/mAt3xBGaobw" "url": "https://example.com/acme/cert/mAt3xBGaobw"
}), }),
"payload": "", "payload": "",
"signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps" "signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps"
} }
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Type: application/pem-certificate-chain Content-Type: application/pem-certificate-chain
Link: <https://example.com/acme/some-directory>;rel="index" Link: <https://example.com/acme/directory>;rel="index"
-----BEGIN CERTIFICATE----- -----BEGIN CERTIFICATE-----
[End-entity certificate contents] [End-entity certificate contents]
-----END CERTIFICATE----- -----END CERTIFICATE-----
-----BEGIN CERTIFICATE----- -----BEGIN CERTIFICATE-----
[Issuer certificate contents] [Issuer certificate contents]
-----END CERTIFICATE----- -----END CERTIFICATE-----
-----BEGIN CERTIFICATE----- -----BEGIN CERTIFICATE-----
[Other certificate contents] [Other certificate contents]
-----END CERTIFICATE----- -----END CERTIFICATE-----
skipping to change at page 51, line 18 skipping to change at page 53, line 19
The identifier authorization process establishes the authorization of The identifier authorization process establishes the authorization of
an account to manage certificates for a given identifier. This an account to manage certificates for a given identifier. This
process assures the server of two things: process assures the server of two things:
1. That the client controls the private key of the account key pair, 1. That the client controls the private key of the account key pair,
and and
2. That the client controls the identifier in question. 2. That the client controls the identifier in question.
This process may be repeated to associate multiple identifiers to a This process may be repeated to associate multiple identifiers with
key pair (e.g., to request certificates with multiple identifiers), an account (e.g., to request certificates with multiple identifiers)
or to associate multiple accounts with an identifier (e.g., to allow or to associate multiple accounts with an identifier (e.g., to allow
multiple entities to manage certificates). multiple entities to manage certificates).
Authorization resources are created by the server in response to Authorization resources are created by the server in response to
certificate orders or authorization requests submitted by an account newOrder or newAuthz requests submitted by an account key holder;
key holder; their URLs are provided to the client in the responses to their URLs are provided to the client in the responses to these
these requests. The authorization object is implicitly tied to the requests. The authorization object is implicitly tied to the account
account key used to sign the request. key used to sign the request.
When a client receives an order from the server in reply to a new When a client receives an order from the server in reply to a
order request, it downloads the authorization resources by sending newOrder request, it downloads the authorization resources by sending
POST-as-GET requests to the indicated URLs. If the client initiates POST-as-GET requests to the indicated URLs. If the client initiates
authorization using a request to the new authorization resource, it authorization using a request to the newAuthz resource, it will have
will have already received the pending authorization object in the already received the pending authorization object in the response to
response to that request. that request.
POST /acme/authz/PAniVnsZcis HTTP/1.1 POST /acme/authz/PAniVnsZcis HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"kid": "https://example.com/acme/acct/evOfKhNU60wg", "kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "uQpSjlRb4vQVCjVYAyyUWg", "nonce": "uQpSjlRb4vQVCjVYAyyUWg",
"url": "https://example.com/acme/authz/1234" "url": "https://example.com/acme/authz/PAniVnsZcis"
}), }),
"payload": "", "payload": "",
"signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps" "signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps"
} }
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Type: application/json Content-Type: application/json
Link: <https://example.com/acme/some-directory>;rel="index" Link: <https://example.com/acme/directory>;rel="index"
{ {
"status": "pending", "status": "pending",
"expires": "2018-03-03T14:09:30Z", "expires": "2016-01-02T14:09:30Z",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.org" "value": "www.example.org"
}, },
"challenges": [ "challenges": [
{ {
"type": "http-01", "type": "http-01",
"url": "https://example.com/acme/chall/prV_B7yEyA4", "url": "https://example.com/acme/chall/prV_B7yEyA4",
"token": "DGyRejmCefe7v4NfDGDKfA" "token": "DGyRejmCefe7v4NfDGDKfA"
}, },
{ {
"type": "dns-01", "type": "dns-01",
"url": "https://example.com/acme/chall/Rg5dV14Gh1Q", "url": "https://example.com/acme/chall/Rg5dV14Gh1Q",
"token": "DGyRejmCefe7v4NfDGDKfA" "token": "DGyRejmCefe7v4NfDGDKfA"
} }
], ]
"wildcard": false
} }
7.5.1. Responding to Challenges 7.5.1. Responding to Challenges
To prove control of the identifier and receive authorization, the To prove control of the identifier and receive authorization, the
client needs to provision the required challenge response based on client needs to provision the required challenge response based on
the challenge type and indicate to the server that it is ready for the challenge type and indicate to the server that it is ready for
the challenge validation to be attempted. the challenge validation to be attempted.
The client indicates to the server it is ready for the challenge The client indicates to the server that it is ready for the challenge
validation by sending an empty JSON body ("{}"), carried in a POST validation by sending an empty JSON body ("{}") carried in a POST
request to the challenge URL (not authorization URL). request to the challenge URL (not the authorization URL).
For example, if the client were to respond to the "http-01" challenge For example, if the client were to respond to the "http-01" challenge
in the above authorization, it would send the following request: in the above authorization, it would send the following request:
POST /acme/chall/prV_B7yEyA4 HTTP/1.1 POST /acme/chall/prV_B7yEyA4 HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
skipping to change at page 53, line 38 skipping to change at page 55, line 31
"url": "https://example.com/acme/chall/prV_B7yEyA4" "url": "https://example.com/acme/chall/prV_B7yEyA4"
}), }),
"payload": base64url({}), "payload": base64url({}),
"signature": "9cbg5JO1Gf5YLjjz...SpkUfcdPai9uVYYQ" "signature": "9cbg5JO1Gf5YLjjz...SpkUfcdPai9uVYYQ"
} }
The server updates the authorization document by updating its The server updates the authorization document by updating its
representation of the challenge with the response object provided by representation of the challenge with the response object provided by
the client. The server MUST ignore any fields in the response object the client. The server MUST ignore any fields in the response object
that are not specified as response fields for this type of challenge. that are not specified as response fields for this type of challenge.
The server provides a 200 (OK) response with the updated challenge Note that the challenges in this document do not define any response
object as its body. fields, but future specifications might define them. The server
provides a 200 (OK) response with the updated challenge object as its
body.
If the client's response is invalid for any reason or does not If the client's response is invalid for any reason or does not
provide the server with appropriate information to validate the provide the server with appropriate information to validate the
challenge, then the server MUST return an HTTP error. On receiving challenge, then the server MUST return an HTTP error. On receiving
such an error, the client SHOULD undo any actions that have been such an error, the client SHOULD undo any actions that have been
taken to fulfill the challenge, e.g., removing files that have been taken to fulfill the challenge, e.g., removing files that have been
provisioned to a web server. provisioned to a web server.
The server is said to "finalize" the authorization when it has The server is said to "finalize" the authorization when it has
completed one of the validations, by assigning the authorization a completed one of the validations. This is done by assigning the
status of "valid" or "invalid", corresponding to whether it considers authorization a status of "valid" or "invalid", corresponding to
the account authorized for the identifier. If the final state is whether it considers the account authorized for the identifier. If
"valid", then the server MUST include an "expires" field. When the final state is "valid", then the server MUST include an "expires"
finalizing an authorization, the server MAY remove challenges other field. When finalizing an authorization, the server MAY remove
than the one that was completed, and may modify the "expires" field. challenges other than the one that was completed, and it may modify
The server SHOULD NOT remove challenges with status "invalid". the "expires" field. The server SHOULD NOT remove challenges with
status "invalid".
Usually, the validation process will take some time, so the client Usually, the validation process will take some time, so the client
will need to poll the authorization resource to see when it is will need to poll the authorization resource to see when it is
finalized. For challenges where the client can tell when the server finalized. For challenges where the client can tell when the server
has validated the challenge (e.g., by seeing an HTTP or DNS request has validated the challenge (e.g., by seeing an HTTP or DNS request
from the server), the client SHOULD NOT begin polling until it has from the server), the client SHOULD NOT begin polling until it has
seen the validation request from the server. seen the validation request from the server.
To check on the status of an authorization, the client sends a POST- To check on the status of an authorization, the client sends a POST-
as-GET request to the authorization URL, and the server responds with as-GET request to the authorization URL, and the server responds with
skipping to change at page 55, line 22 skipping to change at page 57, line 22
"kid": "https://example.com/acme/acct/evOfKhNU60wg", "kid": "https://example.com/acme/acct/evOfKhNU60wg",
"nonce": "uQpSjlRb4vQVCjVYAyyUWg", "nonce": "uQpSjlRb4vQVCjVYAyyUWg",
"url": "https://example.com/acme/authz/PAniVnsZcis" "url": "https://example.com/acme/authz/PAniVnsZcis"
}), }),
"payload": "", "payload": "",
"signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps" "signature": "nuSDISbWG8mMgE7H...QyVUL68yzf3Zawps"
} }
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Type: application/json Content-Type: application/json
Link: <https://example.com/acme/directory>;rel="index"
{ {
"status": "valid", "status": "valid",
"expires": "2018-09-09T14:09:01.13Z", "expires": "2018-09-09T14:09:01.13Z",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.org" "value": "www.example.org"
}, },
"challenges": [ "challenges": [
{ {
"type": "http-01", "type": "http-01",
"url": "https://example.com/acme/chall/prV_B7yEyA4", "url": "https://example.com/acme/chall/prV_B7yEyA4",
"status": "valid", "status": "valid",
"validated": "2014-12-01T12:05:13.72Z", "validated": "2014-12-01T12:05:13.72Z",
"token": "IlirfxKKXAsHtmzK29Pj8A" "token": "IlirfxKKXAsHtmzK29Pj8A"
} }
], ]
"wildcard": false
} }
7.5.2. Deactivating an Authorization 7.5.2. Deactivating an Authorization
If a client wishes to relinquish its authorization to issue If a client wishes to relinquish its authorization to issue
certificates for an identifier, then it may request that the server certificates for an identifier, then it may request that the server
deactivates each authorization associated with it by sending POST deactivate each authorization associated with it by sending POST
requests with the static object {"status": "deactivated"} to each requests with the static object {"status": "deactivated"} to each
authorization URL. authorization URL.
POST /acme/authz/PAniVnsZcis HTTP/1.1 POST /acme/authz/PAniVnsZcis HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
skipping to change at page 56, line 44 skipping to change at page 58, line 44
a JWS object whose JSON payload contains the certificate to be a JWS object whose JSON payload contains the certificate to be
revoked: revoked:
certificate (required, string): The certificate to be revoked, in certificate (required, string): The certificate to be revoked, in
the base64url-encoded version of the DER format. (Note: Because the base64url-encoded version of the DER format. (Note: Because
this field uses base64url, and does not include headers, it is this field uses base64url, and does not include headers, it is
different from PEM.) different from PEM.)
reason (optional, int): One of the revocation reasonCodes defined in reason (optional, int): One of the revocation reasonCodes defined in
Section 5.3.1 of [RFC5280] to be used when generating OCSP Section 5.3.1 of [RFC5280] to be used when generating OCSP
responses and CRLs. If this field is not set the server SHOULD responses and CRLs. If this field is not set, the server SHOULD
omit the reasonCode CRL entry extension when generating OCSP omit the reasonCode CRL entry extension when generating OCSP
responses and CRLs. The server MAY disallow a subset of responses and CRLs. The server MAY disallow a subset of
reasonCodes from being used by the user. If a request contains a reasonCodes from being used by the user. If a request contains a
disallowed reasonCode the server MUST reject it with the error disallowed reasonCode, then the server MUST reject it with the
type "urn:ietf:params:acme:error:badRevocationReason". The error type "urn:ietf:params:acme:error:badRevocationReason". The
problem document detail SHOULD indicate which reasonCodes are problem document detail SHOULD indicate which reasonCodes are
allowed. allowed.
Revocation requests are different from other ACME requests in that Revocation requests are different from other ACME requests in that
they can be signed either with an account key pair or the key pair in they can be signed with either an account key pair or the key pair in
the certificate. the certificate.
Example using an account key pair for the signature: Example using an account key pair for the signature:
POST /acme/revoke-cert HTTP/1.1 POST /acme/revoke-cert HTTP/1.1
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
skipping to change at page 58, line 16 skipping to change at page 60, line 20
o an account that holds authorizations for all of the identifiers in o an account that holds authorizations for all of the identifiers in
the certificate. the certificate.
The server MUST also consider a revocation request valid if it is The server MUST also consider a revocation request valid if it is
signed with the private key corresponding to the public key in the signed with the private key corresponding to the public key in the
certificate. certificate.
If the revocation succeeds, the server responds with status code 200 If the revocation succeeds, the server responds with status code 200
(OK). If the revocation fails, the server returns an error. For (OK). If the revocation fails, the server returns an error. For
example, if the certificate has already been revoked the server example, if the certificate has already been revoked, the server
returns an error response with status code 400 (Bad Request) and type returns an error response with status code 400 (Bad Request) and type
"urn:ietf:params:acme:error:alreadyRevoked". "urn:ietf:params:acme:error:alreadyRevoked".
HTTP/1.1 200 OK HTTP/1.1 200 OK
Replay-Nonce: IXVHDyxIRGcTE0VSblhPzw Replay-Nonce: IXVHDyxIRGcTE0VSblhPzw
Content-Length: 0 Content-Length: 0
Link: <https://example.com/acme/directory>;rel="index"
--- or --- --- or ---
HTTP/1.1 403 Forbidden HTTP/1.1 403 Forbidden
Replay-Nonce: IXVHDyxIRGcTE0VSblhPzw Replay-Nonce: lXfyFzi6238tfPQRwgfmPU
Content-Type: application/problem+json Content-Type: application/problem+json
Content-Language: en Content-Language: en
Link: <https://example.com/acme/directory>;rel="index"
{ {
"type": "urn:ietf:params:acme:error:unauthorized", "type": "urn:ietf:params:acme:error:unauthorized",
"detail": "No authorization provided for name example.net" "detail": "No authorization provided for name example.org"
} }
8. Identifier Validation Challenges 8. Identifier Validation Challenges
There are few types of identifiers in the world for which there is a There are few types of identifiers in the world for which there is a
standardized mechanism to prove possession of a given identifier. In standardized mechanism to prove possession of a given identifier. In
all practical cases, CAs rely on a variety of means to test whether all practical cases, CAs rely on a variety of means to test whether
an entity applying for a certificate with a given identifier actually an entity applying for a certificate with a given identifier actually
controls that identifier. controls that identifier.
Challenges provide the server with assurance that an account holder Challenges provide the server with assurance that an account holder
is also the entity that controls an identifier. For each type of is also the entity that controls an identifier. For each type of
challenge, it must be the case that in order for an entity to challenge, it must be the case that, in order for an entity to
successfully complete the challenge the entity must both: successfully complete the challenge, the entity must both:
o Hold the private key of the account key pair used to respond to o Hold the private key of the account key pair used to respond to
the challenge the challenge, and
o Control the identifier in question.
o Control the identifier in question
Section 10 documents how the challenges defined in this document meet Section 10 documents how the challenges defined in this document meet
these requirements. New challenges will need to document how they these requirements. New challenges will need to document how they
do. do.
ACME uses an extensible challenge/response framework for identifier ACME uses an extensible challenge/response framework for identifier
validation. The server presents a set of challenges in the validation. The server presents a set of challenges in the
authorization object it sends to a client (as objects in the authorization object it sends to a client (as objects in the
"challenges" array), and the client responds by sending a response "challenges" array), and the client responds by sending a response
object in a POST request to a challenge URL. object in a POST request to a challenge URL.
skipping to change at page 59, line 32 skipping to change at page 61, line 43
of an identifier of an identifier
Challenge objects all contain the following basic fields: Challenge objects all contain the following basic fields:
type (required, string): The type of challenge encoded in the type (required, string): The type of challenge encoded in the
object. object.
url (required, string): The URL to which a response can be posted. url (required, string): The URL to which a response can be posted.
status (required, string): The status of this challenge. Possible status (required, string): The status of this challenge. Possible
values are: "pending", "processing", "valid", and "invalid". (See values are "pending", "processing", "valid", and "invalid" (see
Section 7.1.6) Section 7.1.6).
validated (optional, string): The time at which the server validated validated (optional, string): The time at which the server validated
this challenge, encoded in the format specified in RFC 3339 this challenge, encoded in the format specified in [RFC3339].
[RFC3339]. This field is REQUIRED if the "status" field is This field is REQUIRED if the "status" field is "valid".
"valid".
error (optional, object): Error that occurred while the server was error (optional, object): Error that occurred while the server was
validating the challenge, if any, structured as a problem document validating the challenge, if any, structured as a problem document
[RFC7807]. Multiple errors can be indicated by using subproblems [RFC7807]. Multiple errors can be indicated by using subproblems
Section 6.7.1. A challenge object with an error MUST have status Section 6.7.1. A challenge object with an error MUST have status
equal to "invalid". equal to "invalid".
All additional fields are specified by the challenge type. If the All additional fields are specified by the challenge type. If the
server sets a challenge's "status" to "invalid", it SHOULD also server sets a challenge's "status" to "invalid", it SHOULD also
include the "error" field to help the client diagnose why the include the "error" field to help the client diagnose why the
skipping to change at page 60, line 21 skipping to change at page 62, line 32
The identifier validation challenges described in this section all The identifier validation challenges described in this section all
relate to validation of domain names. If ACME is extended in the relate to validation of domain names. If ACME is extended in the
future to support other types of identifiers, there will need to be future to support other types of identifiers, there will need to be
new challenge types, and they will need to specify which types of new challenge types, and they will need to specify which types of
identifier they apply to. identifier they apply to.
8.1. Key Authorizations 8.1. Key Authorizations
All challenges defined in this document make use of a key All challenges defined in this document make use of a key
authorization string. A key authorization is a string that authorization string. A key authorization is a string that
concatinates the token for the challenge with a key fingerprint, concatenates the token for the challenge with a key fingerprint,
separated by a "." character: separated by a "." character:
keyAuthorization = token || '.' || base64url(Thumbprint(accountKey)) keyAuthorization = token || '.' || base64url(Thumbprint(accountKey))
The "Thumbprint" step indicates the computation specified in The "Thumbprint" step indicates the computation specified in
[RFC7638], using the SHA-256 digest [FIPS180-4]. As noted in [RFC7638], using the SHA-256 digest [FIPS180-4]. As noted in
[RFC7518] any prepended zero octets in the fields of a JWK object [RFC7518] any prepended zero octets in the fields of a JWK object
MUST be stripped before doing the computation. MUST be stripped before doing the computation.
As specified in the individual challenges below, the token for a As specified in the individual challenges below, the token for a
challenge is a string comprised entirely of characters in the URL- challenge is a string comprised entirely of characters in the URL-
safe base64 alphabet. The "||" operator indicates concatenation of safe base64 alphabet. The "||" operator indicates concatenation of
strings. strings.
8.2. Retrying Challenges 8.2. Retrying Challenges
ACME challenges typically require the client to set up some network- ACME challenges typically require the client to set up some network-
accessible resource that the server can query in order to validate accessible resource that the server can query in order to validate
that the client controls an identifier. In practice it is not that the client controls an identifier. In practice, it is not
uncommon for the server's queries to fail while a resource is being uncommon for the server's queries to fail while a resource is being
set up, e.g., due to information propagating across a cluster or set up, e.g., due to information propagating across a cluster or
firewall rules not being in place. firewall rules not being in place.
Clients SHOULD NOT respond to challenges until they believe that the Clients SHOULD NOT respond to challenges until they believe that the
server's queries will succeed. If a server's initial validation server's queries will succeed. If a server's initial validation
query fails, the server SHOULD retry the query after some time, in query fails, the server SHOULD retry the query after some time, in
order to account for delay in setting up responses such as DNS order to account for delay in setting up responses such as DNS
records or HTTP resources. The precise retry schedule is up to the records or HTTP resources. The precise retry schedule is up to the
server, but server operators should keep in mind the operational server, but server operators should keep in mind the operational
skipping to change at page 61, line 41 skipping to change at page 64, line 12
server challenges the client to provision a file at a specific path, server challenges the client to provision a file at a specific path,
with a specific string as its content. with a specific string as its content.
As a domain may resolve to multiple IPv4 and IPv6 addresses, the As a domain may resolve to multiple IPv4 and IPv6 addresses, the
server will connect to at least one of the hosts found in the DNS A server will connect to at least one of the hosts found in the DNS A
and AAAA records, at its discretion. Because many web servers and AAAA records, at its discretion. Because many web servers
allocate a default HTTPS virtual host to a particular low-privilege allocate a default HTTPS virtual host to a particular low-privilege
tenant user in a subtle and non-intuitive manner, the challenge must tenant user in a subtle and non-intuitive manner, the challenge must
be completed over HTTP, not HTTPS. be completed over HTTP, not HTTPS.
type (required, string): The string "http-01" type (required, string): The string "http-01".
token (required, string): A random value that uniquely identifies token (required, string): A random value that uniquely identifies
the challenge. This value MUST have at least 128 bits of entropy. the challenge. This value MUST have at least 128 bits of entropy.
It MUST NOT contain any characters outside the base64url alphabet, It MUST NOT contain any characters outside the base64url alphabet
and MUST NOT include base64 padding characters ("="). See and MUST NOT include base64 padding characters ("="). See
[RFC4086] for additional information on randomness requirements. [RFC4086] for additional information on randomness requirements.
{ {
"type": "http-01", "type": "http-01",
"url": "https://example.com/acme/chall/prV_B7yEyA4", "url": "https://example.com/acme/chall/prV_B7yEyA4",
"status": "pending", "status": "pending",
"token": "LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0" "token": "LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0"
} }
skipping to change at page 63, line 44 skipping to change at page 66, line 13
Section 10.2 for security considerations related to redirects. Section 10.2 for security considerations related to redirects.
If all of the above verifications succeed, then the validation is If all of the above verifications succeed, then the validation is
successful. If the request fails, or the body does not pass these successful. If the request fails, or the body does not pass these
checks, then it has failed. checks, then it has failed.
The client SHOULD de-provision the resource provisioned for this The client SHOULD de-provision the resource provisioned for this
challenge once the challenge is complete, i.e., once the "status" challenge once the challenge is complete, i.e., once the "status"
field of the challenge has the value "valid" or "invalid". field of the challenge has the value "valid" or "invalid".
Note that becuase the token appears both in the request sent by the Note that because the token appears both in the request sent by the
ACME server and in the key authorization in the response, it is ACME server and in the key authorization in the response, it is
possible to build clients that copy the token from request to possible to build clients that copy the token from request to
response. Clients should avoid this behavior, because it can lead to response. Clients should avoid this behavior because it can lead to
cross-site scripting vulnerabilities; instead, clients should be cross-site scripting vulnerabilities; instead, clients should be
explicitly configured on a per-challenge basis. A client that does explicitly configured on a per-challenge basis. A client that does
copy tokens from requests to responses MUST validate that the token copy tokens from requests to responses MUST validate that the token
in the request matches the token syntax above (e.g., that it includes in the request matches the token syntax above (e.g., that it includes
only characters from the base64url alphabet). only characters from the base64url alphabet).
8.4. DNS Challenge 8.4. DNS Challenge
When the identifier being validated is a domain name, the client can When the identifier being validated is a domain name, the client can
prove control of that domain by provisioning a TXT resource record prove control of that domain by provisioning a TXT resource record
containing a designated value for a specific validation domain name. containing a designated value for a specific validation domain name.
type (required, string): The string "dns-01" type (required, string): The string "dns-01".
token (required, string): A random value that uniquely identifies token (required, string): A random value that uniquely identifies
the challenge. This value MUST have at least 128 bits of entropy. the challenge. This value MUST have at least 128 bits of entropy.
It MUST NOT contain any characters outside the base64url alphabet, It MUST NOT contain any characters outside the base64url alphabet,
including padding characters ("="). See [RFC4086] for additional including padding characters ("="). See [RFC4086] for additional
information on randomness requirements. information on randomness requirements.
{ {
"type": "dns-01", "type": "dns-01",
"url": "https://example.com/acme/chall/Rg5dV14Gh1Q", "url": "https://example.com/acme/chall/Rg5dV14Gh1Q",
skipping to change at page 64, line 38 skipping to change at page 67, line 5
A client fulfills this challenge by constructing a key authorization A client fulfills this challenge by constructing a key authorization
from the "token" value provided in the challenge and the client's from the "token" value provided in the challenge and the client's
account key. The client then computes the SHA-256 digest [FIPS180-4] account key. The client then computes the SHA-256 digest [FIPS180-4]
of the key authorization. of the key authorization.
The record provisioned to the DNS contains the base64url encoding of The record provisioned to the DNS contains the base64url encoding of
this digest. The client constructs the validation domain name by this digest. The client constructs the validation domain name by
prepending the label "_acme-challenge" to the domain name being prepending the label "_acme-challenge" to the domain name being
validated, then provisions a TXT record with the digest value under validated, then provisions a TXT record with the digest value under
that name. For example, if the domain name being validated is that name. For example, if the domain name being validated is
"example.org", then the client would provision the following DNS "www.example.org", then the client would provision the following DNS
record: record:
_acme-challenge.example.org. 300 IN TXT "gfj9Xq...Rg85nM" _acme-challenge.www.example.org. 300 IN TXT "gfj9Xq...Rg85nM"
A client responds with an empty object ({}) to acknowledge that the A client responds with an empty object ({}) to acknowledge that the
challenge can be validated by the server. challenge can be validated by the server.
POST /acme/chall/Rg5dV14Gh1Q POST /acme/chall/Rg5dV14Gh1Q
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
"protected": base64url({ "protected": base64url({
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If all of the above verifications succeed, then the validation is If all of the above verifications succeed, then the validation is
successful. If no DNS record is found, or DNS record and response successful. If no DNS record is found, or DNS record and response
payload do not pass these checks, then the validation fails. payload do not pass these checks, then the validation fails.
The client SHOULD de-provision the resource record(s) provisioned for The client SHOULD de-provision the resource record(s) provisioned for
this challenge once the challenge is complete, i.e., once the this challenge once the challenge is complete, i.e., once the
"status" field of the challenge has the value "valid" or "invalid". "status" field of the challenge has the value "valid" or "invalid".
9. IANA Considerations 9. IANA Considerations
9.1. MIME Type: application/pem-certificate-chain 9.1. Media Type: application/pem-certificate-chain
A file of this type contains one or more certificates encoded with A file of this type contains one or more certificates encoded with
the PEM textual encoding, according to RFC 7468 [RFC7468]. The the PEM textual encoding, according to [RFC7468]. The textual
textual encoding of certificates in this file MUST use the strict encoding of certificates in this file MUST use the strict encoding
encoding and MUST NOT include explanatory text. The ABNF for this and MUST NOT include explanatory text. The ABNF for this format is
format is as follows, where "stricttextualmsg" and "eol" are as as follows, where "stricttextualmsg" and "eol" are as defined in
defined in Section 3 of RFC 7468: Section 3 of RFC 7468:
certchain = stricttextualmsg *(eol stricttextualmsg) certchain = stricttextualmsg *(eol stricttextualmsg)
In order to provide easy interoperation with TLS, the first In order to provide easy interoperation with TLS, the first
certificate MUST be an end-entity certificate. Each following certificate MUST be an end-entity certificate. Each following
certificate SHOULD directly certify the one preceding it. Because certificate SHOULD directly certify the one preceding it. Because
certificate validation requires that trust anchors be distributed certificate validation requires that trust anchors be distributed
independently, a certificate that represents a trust anchor MAY be independently, a certificate that represents a trust anchor MAY be
omitted from the chain, provided that supported peers are known to omitted from the chain, provided that supported peers are known to
possess any omitted certificates. possess any omitted certificates.
The "Media Types" registry should be updated with the following The following has been registered in the "Media Types" registry:
additional value: Type name: application
MIME media type name: application
MIME subtype name: pem-certificate-chain Subtype name: pem-certificate-chain
Required parameters: None Required parameters: None
Optional parameters: None Optional parameters: None
Encoding considerations: 7bit Encoding considerations: 7bit
Security considerations: Carries a cryptographic certificate and its Security considerations: Carries a cryptographic certificate and its
associated certificate chain. This media type carries no active associated certificate chain. This media type carries no active
content. content.
Interoperability considerations: None Interoperability considerations: None
Published specification: draft-ietf-acme-acme [[ RFC EDITOR: Please Published specification: RFC 8555
replace draft-ietf-acme-acme above with the RFC number assigned to
this ]]
Applications which use this media type: ACME clients and servers, Applications that use this media type: ACME clients and servers, HTTP
HTTP servers, other applications that need to be configured with a servers, other applications that need to be configured with a
certificate chain certificate chain
Additional information: Additional information:
Deprecated alias names for this type: n/a Magic number(s): n/a File Deprecated alias names for this type: n/a
extension(s): .pem Macintosh file type code(s): n/a Magic number(s): n/a
File extension(s): .pem
Macintosh file type code(s): n/a
Person & email address to contact for further information: See Person & email address to contact for further information: See
Authors' Addresses section. Authors' Addresses section.
Intended usage: COMMON Intended usage: COMMON
Restrictions on usage: n/a Restrictions on usage: n/a
Author: See Authors' Addresses section. Author: See Authors' Addresses section.
Change controller: Internet Engineering Task Force iesg@ietf.org [2] Change controller: IETF <iesg@ietf.org>
9.2. Well-Known URI for the HTTP Challenge 9.2. Well-Known URI for the HTTP Challenge
The "Well-Known URIs" registry should be updated with the following The following value has been registered in the "Well-Known URIs"
additional value (using the template from [RFC5785]): registry (using the template from [RFC5785]):
URI suffix: acme-challenge URI suffix: acme-challenge
Change controller: IETF Change controller: IETF
Specification document(s): This document, Section Section 8.3 Specification document(s): RFC 8555, Section 8.3
Related information: N/A Related information: N/A
9.3. Replay-Nonce HTTP Header 9.3. Replay-Nonce HTTP Header
The "Message Headers" registry should be updated with the following The following value has been registered in the "Message Headers"
additional value: registry:
+------------------+----------+----------+--------------------------+ +-------------------+----------+----------+-------------------------+
| Header Field | Protocol | Status | Reference | | Header Field Name | Protocol | Status | Reference |
| Name | | | | +-------------------+----------+----------+-------------------------+
+------------------+----------+----------+--------------------------+ | Replay-Nonce | http | standard | RFC 8555, Section 6.5.1 |
| Replay-Nonce | http | standard | [[this-RFC, Section | +-------------------+----------+----------+-------------------------+
| | | | 6.5.1] |
+------------------+----------+----------+--------------------------+
9.4. "url" JWS Header Parameter 9.4. "url" JWS Header Parameter
The "JSON Web Signature and Encryption Header Parameters" registry The following value has been registered in the "JSON Web Signature
should be updated with the following additional value: and Encryption Header Parameters" registry:
o Header Parameter Name: "url" o Header Parameter Name: "url"
o Header Parameter Description: URL o Header Parameter Description: URL
o Header Parameter Usage Location(s): JWE, JWS o Header Parameter Usage Location(s): JWE, JWS
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 6.4.1 of RFC XXXX o Specification Document(s): RFC 8555, Section 6.4.1
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.5. "nonce" JWS Header Parameter 9.5. "nonce" JWS Header Parameter
The "JSON Web Signature and Encryption Header Parameters" registry The following value has been registered in the "JSON Web Signature
should be updated with the following additional value: and Encryption Header Parameters" registry:
o Header Parameter Name: "nonce" o Header Parameter Name: "nonce"
o Header Parameter Description: Nonce o Header Parameter Description: Nonce
o Header Parameter Usage Location(s): JWE, JWS o Header Parameter Usage Location(s): JWE, JWS
o Change Controller: IESG o Change Controller: IESG
o Specification Document(s): Section 6.5.2 of RFC XXXX o Specification Document(s): RFC 8555, Section 6.5.2
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.6. URN Sub-namespace for ACME (urn:ietf:params:acme) 9.6. URN Sub-namespace for ACME (urn:ietf:params:acme)
The "IETF URN Sub-namespace for Registered Protocol Parameter The following value has been registered in the "IETF URN Sub-
Identifiers" registry should be updated with the following additional namespace for Registered Protocol Parameter Identifiers" registry,
value, following the template in [RFC3553]: following the template in [RFC3553]:
Registry name: acme Registry name: acme
Specification: RFC XXXX Specification: RFC 8555
Repository: URL-TBD Repository: http://www.iana.org/assignments/acme
Index value: No transformation needed. Index value: No transformation needed.
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document, and replace URL-TBD with the URL assigned by IANA
for registries of ACME parameters. ]]
9.7. New Registries 9.7. New Registries
This document requests that IANA create the following new registries: IANA has created the following registries:
1. ACME Account Object Fields (Section 9.7.1) 1. ACME Account Object Fields (Section 9.7.1)
2. ACME Order Object Fields (Section 9.7.2) 2. ACME Order Object Fields (Section 9.7.2)
3. ACME Authorization Object Fields (Section 9.7.3) 3. ACME Authorization Object Fields (Section 9.7.3)
4. ACME Error Types (Section 9.7.4) 4. ACME Error Types (Section 9.7.4)
5. ACME Resource Types (Section 9.7.5) 5. ACME Resource Types (Section 9.7.5)
6. ACME Directory Metadata Fields (Section 9.7.6) 6. ACME Directory Metadata Fields (Section 9.7.6)
7. ACME Identifier Types (Section 9.7.7) 7. ACME Identifier Types (Section 9.7.7)
8. ACME Validation Methods (Section 9.7.8) 8. ACME Validation Methods (Section 9.7.8)
All of these registries are under a heading of "Automated Certificate All of these registries are under a heading of "Automated Certificate
Management Environment (ACME) Protocol" and are administered under a Management Environment (ACME) Protocol" and are administered under a
skipping to change at page 69, line 18 skipping to change at page 71, line 31
7. ACME Identifier Types (Section 9.7.7) 7. ACME Identifier Types (Section 9.7.7)
8. ACME Validation Methods (Section 9.7.8) 8. ACME Validation Methods (Section 9.7.8)
All of these registries are under a heading of "Automated Certificate All of these registries are under a heading of "Automated Certificate
Management Environment (ACME) Protocol" and are administered under a Management Environment (ACME) Protocol" and are administered under a
Specification Required policy [RFC8126]. Specification Required policy [RFC8126].
9.7.1. Fields in Account Objects 9.7.1. Fields in Account Objects
This registry lists field names that are defined for use in ACME The "ACME Account Object Fields" registry lists field names that are
account objects. Fields marked as "configurable" may be included in defined for use in ACME account objects. Fields marked as
a new-account request. "configurable" may be included in a newAccount request.
Template: Template:
o Field name: The string to be used as a field name in the JSON o Field name: The string to be used as a field name in the JSON
object object
o Field type: The type of value to be provided, e.g., string, o Field type: The type of value to be provided, e.g., string,
boolean, array of string boolean, array of string
o Requests: Either the value "none" or a list of types of requests o Requests: Either the value "none" or a list of types of requests
skipping to change at page 69, line 39 skipping to change at page 72, line 4
o Requests: Either the value "none" or a list of types of requests o Requests: Either the value "none" or a list of types of requests
where the field is allowed in a request object, taken from the where the field is allowed in a request object, taken from the
following values: following values:
* "new" - Requests to the "newAccount" URL * "new" - Requests to the "newAccount" URL
* "account" - Requests to an account URL * "account" - Requests to an account URL
o Reference: Where this field is defined o Reference: Where this field is defined
Initial contents: The fields and descriptions defined in Initial contents: The fields and descriptions defined in
Section 7.1.2. Section 7.1.2.
+------------------------+---------------+--------------+-----------+ +------------------------+---------------+--------------+-----------+
| Field Name | Field Type | Requests | Reference | | Field Name | Field Type | Requests | Reference |
+------------------------+---------------+--------------+-----------+ +------------------------+---------------+--------------+-----------+
| status | string | new, account | RFC XXXX | | status | string | new, account | RFC 8555 |
| | | | | | | | | |
| contact | array of | new, account | RFC XXXX | | contact | array of | new, account | RFC 8555 |
| | string | | | | | string | | |
| | | | | | | | | |
| externalAccountBinding | object | new | RFC XXXX | | externalAccountBinding | object | new | RFC 8555 |
| | | | | | | | | |
| termsOfServiceAgreed | boolean | new | RFC XXXX | | termsOfServiceAgreed | boolean | new | RFC 8555 |
| | | | | | | | | |
| orders | string | none | RFC XXXX | | onlyReturnExisting | boolean | new | RFC 8555 |
| | | | |
| orders | string | none | RFC 8555 |
+------------------------+---------------+--------------+-----------+ +------------------------+---------------+--------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.2. Fields in Order Objects 9.7.2. Fields in Order Objects
This registry lists field names that are defined for use in ACME The "ACME Order Object Fields" registry lists field names that are
order objects. Fields marked as "configurable" may be included in a defined for use in ACME order objects. Fields marked as
new-order request. "configurable" may be included in a newOrder request.
Template: Template:
o Field name: The string to be used as a field name in the JSON o Field name: The string to be used as a field name in the JSON
object object
o Field type: The type of value to be provided, e.g., string, o Field type: The type of value to be provided, e.g., string,
boolean, array of string boolean, array of string
o Client configurable: Boolean indicating whether the server should o Configurable: Boolean indicating whether the server should accept
accept values provided by the client values provided by the client
o Reference: Where this field is defined o Reference: Where this field is defined
Initial contents: The fields and descriptions defined in Initial contents: The fields and descriptions defined in
Section 7.1.3. Section 7.1.3.
+----------------+-----------------+--------------+-----------+ +----------------+-----------------+--------------+-----------+
| Field Name | Field Type | Configurable | Reference | | Field Name | Field Type | Configurable | Reference |
+----------------+-----------------+--------------+-----------+ +----------------+-----------------+--------------+-----------+
| status | string | false | RFC XXXX | | status | string | false | RFC 8555 |
| | | | | | | | | |
| expires | string | false | RFC XXXX | | expires | string | false | RFC 8555 |
| | | | | | | | | |
| identifiers | array of object | true | RFC XXXX | | identifiers | array of object | true | RFC 8555 |
| | | | | | | | | |
| notBefore | string | true | RFC XXXX | | notBefore | string | true | RFC 8555 |
| | | | | | | | | |
| notAfter | string | true | RFC XXXX | | notAfter | string | true | RFC 8555 |
| | | | | | | | | |
| authorizations | array of string | false | RFC XXXX | | error | string | false | RFC 8555 |
| | | | | | | | | |
| finalize | string | false | RFC XXXX | | authorizations | array of string | false | RFC 8555 |
| | | | | | | | | |
| certificate | string | false | RFC XXXX | | finalize | string | false | RFC 8555 |
| | | | |
| certificate | string | false | RFC 8555 |
+----------------+-----------------+--------------+-----------+ +----------------+-----------------+--------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.3. Fields in Authorization Objects 9.7.3. Fields in Authorization Objects
This registry lists field names that are defined for use in ACME The "ACME Authorization Object Fields" registry lists field names
authorization objects. Fields marked as "configurable" may be that are defined for use in ACME authorization objects. Fields
included in a new-authorization request. marked as "configurable" may be included in a newAuthz request.
Template: Template:
o Field name: The string to be used as a field name in the JSON o Field name: The string to be used as a field name in the JSON
object object
o Field type: The type of value to be provided, e.g., string, o Field type: The type of value to be provided, e.g., string,
boolean, array of string boolean, array of string
o Client configurable: Boolean indicating whether the server should o Configurable: Boolean indicating whether the server should accept
accept values provided by the client values provided by the client
o Reference: Where this field is defined o Reference: Where this field is defined
Initial contents: The fields and descriptions defined in Initial contents: The fields and descriptions defined in
Section 7.1.4. Section 7.1.4.
+------------+-----------------+--------------+-----------+ +------------+-----------------+--------------+-----------+
| Field Name | Field Type | Configurable | Reference | | Field Name | Field Type | Configurable | Reference |
+------------+-----------------+--------------+-----------+ +------------+-----------------+--------------+-----------+
| identifier | object | true | RFC XXXX | | identifier | object | true | RFC 8555 |
| | | | | | | | | |
| status | string | false | RFC XXXX | | status | string | false | RFC 8555 |
| | | | | | | | | |
| expires | string | false | RFC XXXX | | expires | string | false | RFC 8555 |
| | | | | | | | | |
| challenges | array of object | false | RFC XXXX | | challenges | array of object | false | RFC 8555 |
| | | | | | | | | |
| wildcard | boolean | false | RFC XXXX | | wildcard | boolean | false | RFC 8555 |
+------------+-----------------+--------------+-----------+ +------------+-----------------+--------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.4. Error Types 9.7.4. Error Types
This registry lists values that are used within URN values that are The "ACME Error Types" registry lists values that are used within URN
provided in the "type" field of problem documents in ACME. values that are provided in the "type" field of problem documents in
ACME.
Template: Template:
o Type: The label to be included in the URN for this error, o Type: The label to be included in the URN for this error,
following "urn:ietf:params:acme:error:" following "urn:ietf:params:acme:error:"
o Description: A human-readable description of the error o Description: A human-readable description of the error
o Reference: Where the error is defined o Reference: Where the error is defined
Initial contents: The types and descriptions in the table in Initial contents: The types and descriptions in the table in
Section 6.7 above, with the Reference field set to point to this Section 6.7 above, with the Reference field set to point to this
specification. specification.
9.7.5. Resource Types 9.7.5. Resource Types
This registry lists the types of resources that ACME servers may list The "ACME Resource Types" registry lists the types of resources that
in their directory objects. ACME servers may list in their directory objects.
Template: Template:
o Field name: The value to be used as a field name in the directory o Field name: The value to be used as a field name in the directory
object object
o Resource type: The type of resource labeled by the field o Resource type: The type of resource labeled by the field
o Reference: Where the resource type is defined o Reference: Where the resource type is defined
Initial contents: Initial contents:
+------------+--------------------+-----------+ +------------+--------------------+-----------+
| Field Name | Resource Type | Reference | | Field Name | Resource Type | Reference |
+------------+--------------------+-----------+ +------------+--------------------+-----------+
| newNonce | New nonce | RFC XXXX | | newNonce | New nonce | RFC 8555 |
| | | | | | | |
| newAccount | New account | RFC XXXX | | newAccount | New account | RFC 8555 |
| | | | | | | |
| newOrder | New order | RFC XXXX | | newOrder | New order | RFC 8555 |
| | | | | | | |
| newAuthz | New authorization | RFC XXXX | | newAuthz | New authorization | RFC 8555 |
| | | | | | | |
| revokeCert | Revoke certificate | RFC XXXX | | revokeCert | Revoke certificate | RFC 8555 |
| | | | | | | |
| keyChange | Key change | RFC XXXX | | keyChange | Key change | RFC 8555 |
| | | | | | | |
| meta | Metadata object | RFC XXXX | | meta | Metadata object | RFC 8555 |
+------------+--------------------+-----------+ +------------+--------------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.6. Fields in the "meta" Object within a Directory Object 9.7.6. Fields in the "meta" Object within a Directory Object
This registry lists field names that are defined for use in the JSON The "ACME Directory Metadata Fields" registry lists field names that
object included in the "meta" field of an ACME directory object. are defined for use in the JSON object included in the "meta" field
of an ACME directory object.
Template: Template:
o Field name: The string to be used as a field name in the JSON o Field name: The string to be used as a field name in the JSON
object object
o Field type: The type of value to be provided, e.g., string, o Field type: The type of value to be provided, e.g., string,
boolean, array of string boolean, array of string
o Reference: Where this field is defined o Reference: Where this field is defined
skipping to change at page 73, line 41 skipping to change at page 76, line 4
Template: Template:
o Field name: The string to be used as a field name in the JSON o Field name: The string to be used as a field name in the JSON
object object
o Field type: The type of value to be provided, e.g., string, o Field type: The type of value to be provided, e.g., string,
boolean, array of string boolean, array of string
o Reference: Where this field is defined o Reference: Where this field is defined
Initial contents: The fields and descriptions defined in Initial contents: The fields and descriptions defined in
Section 7.1.1. Section 7.1.1.
+-------------------------+-----------------+-----------+ +-------------------------+-----------------+-----------+
| Field Name | Field Type | Reference | | Field Name | Field Type | Reference |
+-------------------------+-----------------+-----------+ +-------------------------+-----------------+-----------+
| termsOfService | string | RFC XXXX | | termsOfService | string | RFC 8555 |
| | | | | | | |
| website | string | RFC XXXX | | website | string | RFC 8555 |
| | | | | | | |
| caaIdentities | array of string | RFC XXXX | | caaIdentities | array of string | RFC 8555 |
| | | | | | | |
| externalAccountRequired | boolean | RFC XXXX | | externalAccountRequired | boolean | RFC 8555 |
+-------------------------+-----------------+-----------+ +-------------------------+-----------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.7. Identifier Types 9.7.7. Identifier Types
This registry lists the types of identifiers that can be present in The "ACME Identifier Types" registry lists the types of identifiers
ACME authorization objects. that can be present in ACME authorization objects.
Template: Template:
o Label: The value to be put in the "type" field of the identifier o Label: The value to be put in the "type" field of the identifier
object object
o Reference: Where the identifier type is defined o Reference: Where the identifier type is defined
Initial contents: Initial contents:
+-------+-----------+ +-------+-----------+
| Label | Reference | | Label | Reference |
+-------+-----------+ +-------+-----------+
| dns | RFC XXXX | | dns | RFC 8555 |
+-------+-----------+ +-------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.8. Validation Methods 9.7.8. Validation Methods
This registry lists identifiers for the ways that CAs can validate The "ACME Validation Methods" registry lists identifiers for the ways
control of identifiers. Each method's entry must specify whether it that CAs can validate control of identifiers. Each method's entry
corresponds to an ACME challenge type. The "Identifier Type" field must specify whether it corresponds to an ACME challenge type. The
must be contained in the Label column of the ACME Identifier Types "Identifier Type" field must be contained in the Label column of the
registry. "ACME Identifier Types" registry.
Template: Template:
o Label: The identifier for this validation method o Label: The identifier for this validation method
o Identifier Type: The type of identifier that this method applies o Identifier Type: The type of identifier that this method applies
to to
o ACME: "Y" if the validation method corresponds to an ACME o ACME: "Y" if the validation method corresponds to an ACME
challenge type; "N" otherwise challenge type; "N" otherwise
skipping to change at page 75, line 24 skipping to change at page 77, line 26
This registry may also contain reserved entries (e.g., to avoid This registry may also contain reserved entries (e.g., to avoid
collisions). Such entries should have the "ACME" field set to "N" collisions). Such entries should have the "ACME" field set to "N"
and the "Identifier Type" set to "RESERVED". and the "Identifier Type" set to "RESERVED".
Initial Contents Initial Contents
+------------+-----------------+------+-----------+ +------------+-----------------+------+-----------+
| Label | Identifier Type | ACME | Reference | | Label | Identifier Type | ACME | Reference |
+------------+-----------------+------+-----------+ +------------+-----------------+------+-----------+
| http-01 | dns | Y | RFC XXXX | | http-01 | dns | Y | RFC 8555 |
| | | | | | | | | |
| dns-01 | dns | Y | RFC XXXX | | dns-01 | dns | Y | RFC 8555 |
| | | | | | | | | |
| tls-sni-01 | RESERVED | N | RFC XXXX | | tls-sni-01 | RESERVED | N | RFC 8555 |
| | | | | | | | | |
| tls-sni-02 | RESERVED | N | RFC XXXX | | tls-sni-02 | RESERVED | N | RFC 8555 |
+------------+-----------------+------+-----------+ +------------+-----------------+------+-----------+
When evaluating a request for an assignment in this registry, the When evaluating a request for an assignment in this registry, the
designated expert should ensure that the method being registered has designated expert should ensure that the method being registered has
a clear, interoperable definition and does not overlap with existing a clear, interoperable definition and does not overlap with existing
validation methods. That is, it should not be possible for a client validation methods. That is, it should not be possible for a client
and server to follow the same set of actions to fulfill two different and server to follow the same set of actions to fulfill two different
validation methods. validation methods.
The values "tls-sni-01" and "tls-sni-02" are reserved because they The values "tls-sni-01" and "tls-sni-02" are reserved because they
were used in pre-RFC versions of this specification to denote were used in pre-RFC versions of this specification to denote
validation methods that were removed because they were found not to validation methods that were removed because they were found not to
be secure in some cases. be secure in some cases.
Validation methods do not have to be compatible with ACME in order to Validation methods do not have to be compatible with ACME in order to
be registered. For example, a CA might wish to register a validation be registered. For example, a CA might wish to register a validation
method in order to support its use with the ACME extensions to CAA method to support its use with the ACME extensions to CAA [ACME-CAA].
[I-D.ietf-acme-caa].
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
10. Security Considerations 10. Security Considerations
ACME is a protocol for managing certificates that attest to ACME is a protocol for managing certificates that attest to
identifier/key bindings. Thus the foremost security goal of ACME is identifier/key bindings. Thus, the foremost security goal of ACME is
to ensure the integrity of this process, i.e., to ensure that the to ensure the integrity of this process, i.e., to ensure that the
bindings attested by certificates are correct and that only bindings attested by certificates are correct and that only
authorized entities can manage certificates. ACME identifies clients authorized entities can manage certificates. ACME identifies clients
by their account keys, so this overall goal breaks down into two more by their account keys, so this overall goal breaks down into two more
precise goals: precise goals:
1. Only an entity that controls an identifier can get an 1. Only an entity that controls an identifier can get an
authorization for that identifier authorization for that identifier
2. Once authorized, an account key's authorizations cannot be 2. Once authorized, an account key's authorizations cannot be
skipping to change at page 77, line 32 skipping to change at page 79, line 32
but they are different in most cases. Each channel, for example, but they are different in most cases. Each channel, for example,
uses a different communications pattern: the ACME channel will uses a different communications pattern: the ACME channel will
comprise inbound HTTPS connections to the ACME server and the comprise inbound HTTPS connections to the ACME server and the
validation channel outbound HTTP or DNS requests. validation channel outbound HTTP or DNS requests.
Broadly speaking, ACME aims to be secure against active and passive Broadly speaking, ACME aims to be secure against active and passive
attackers on any individual channel. Some vulnerabilities arise attackers on any individual channel. Some vulnerabilities arise
(noted below) when an attacker can exploit both the ACME channel and (noted below) when an attacker can exploit both the ACME channel and
one of the others. one of the others.
On the ACME channel, in addition to network layer attackers, we also On the ACME channel, in addition to network-layer attackers, we also
need to account for man-in-the-middle (MitM) attacks at the need to account for man-in-the-middle (MitM) attacks at the
application layer, and for abusive use of the protocol itself. application layer and for abusive use of the protocol itself.
Protection against application layer MitM addresses potential Protection against application-layer MitM addresses potential
attackers such as Content Distribution Networks (CDNs) and attackers such as Content Distribution Networks (CDNs) and
middleboxes with a TLS MitM function. Preventing abusive use of ACME middleboxes with a TLS MitM function. Preventing abusive use of ACME
means ensuring that an attacker with access to the validation channel means ensuring that an attacker with access to the validation channel
can't obtain illegitimate authorization by acting as an ACME client can't obtain illegitimate authorization by acting as an ACME client
(legitimately, in terms of the protocol). (legitimately, in terms of the protocol).
ACME does not protect against other types of abuse by a MitM on the ACME does not protect against other types of abuse by a MitM on the
ACME channel. For example, such an attacker could send a bogus ACME channel. For example, such an attacker could send a bogus
"badSignatureAlgorithm" error response to downgrade a client to the "badSignatureAlgorithm" error response to downgrade a client to the
lowest-quality signature algorithm that the server supports. A MitM lowest-quality signature algorithm that the server supports. A MitM
that is present on all connections (such as a CDN), can cause denial- that is present on all connections (such as a CDN) can cause denial-
of-service conditions in a variety of ways. of-service conditions in a variety of ways.
10.2. Integrity of Authorizations 10.2. Integrity of Authorizations
ACME allows anyone to request challenges for an identifier by ACME allows anyone to request challenges for an identifier by
registering an account key and sending a new-order request using that registering an account key and sending a newOrder request using that
account key. The integrity of the authorization process thus depends account key. The integrity of the authorization process thus depends
on the identifier validation challenges to ensure that the challenge on the identifier validation challenges to ensure that the challenge
can only be completed by someone who both (1) holds the private key can only be completed by someone who both (1) holds the private key
of the account key pair, and (2) controls the identifier in question. of the account key pair and (2) controls the identifier in question.
Validation responses need to be bound to an account key pair in order Validation responses need to be bound to an account key pair in order
to avoid situations where a MitM on ACME HTTPS requests can switch to avoid situations where a MitM on ACME HTTPS requests can switch
out a legitimate domain holder's account key for one of his choosing. out a legitimate domain holder's account key for one of his choosing.
Such MitMs can arise, for example, if a CA uses a CDN or third-party Such MitMs can arise, for example, if a CA uses a CDN or third-party
reverse proxy in front of its ACME interface. An attack by such an reverse proxy in front of its ACME interface. An attack by such an
MitM could have the following form: MitM could have the following form:
o Legitimate domain holder registers account key pair A 1. Legitimate domain holder registers account key pair A
o MitM registers account key pair B 2. MitM registers account key pair B
o Legitimate domain holder sends a new-order request signed using 3. Legitimate domain holder sends a newOrder request signed using
account key A account key A
o MitM suppresses the legitimate request but sends the same request 4. MitM suppresses the legitimate request but sends the same request
signed using account key B signed using account key B
o ACME server issues challenges and MitM forwards them to the 5. ACME server issues challenges and MitM forwards them to the
legitimate domain holder legitimate domain holder
o Legitimate domain holder provisions the validation response 6. Legitimate domain holder provisions the validation response
o ACME server performs validation query and sees the response 7. ACME server performs validation query and sees the response
provisioned by the legitimate domain holder provisioned by the legitimate domain holder
o Because the challenges were issued in response to a message signed 8. Because the challenges were issued in response to a message
account key B, the ACME server grants authorization to account key signed with account key B, the ACME server grants authorization
B (the MitM) instead of account key A (the legitimate domain to account key B (the MitM) instead of account key A (the
holder) legitimate domain holder)
Domain ACME Domain ACME
Holder MitM Server Holder MitM Server
| | | | | |
| newAccount(A) | | | newAccount(A) | |
|--------------------->|--------------------->| |--------------------->|--------------------->|
| | | | | |
| | newAccount(B) | | | newAccount(B) |
| |--------------------->| | |--------------------->|
| newOrder(domain, A) | | | newOrder(domain, A) | |
skipping to change at page 79, line 31 skipping to change at page 81, line 31
| response(chall, A) | response(chall, B) | | response(chall, A) | response(chall, B) |
|--------------------->|--------------------->| |--------------------->|--------------------->|
| | | | | |
| validation request | | | validation request | |
|<--------------------------------------------| |<--------------------------------------------|
| | | | | |
| validation response | | | validation response | |
|-------------------------------------------->| |-------------------------------------------->|
| | | | | |
| | | Considers challenge | | | Considers challenge
| | | fulfilled by B. | | | fulfilled by B
| | | | | |
Man-in-the-Middle Attack Exploiting a Validation Method without Man-in-the-Middle Attack Exploiting a Validation
Account Key Binding Method without Account Key Binding
All of the challenges defined in this document have a binding between All of the challenges defined in this document have a binding between
the account private key and the validation query made by the server, the account private key and the validation query made by the server,
via the key authorization. The key authorization reflects the via the key authorization. The key authorization reflects the
account public key and is provided to the server in the validation account public key and is provided to the server in the validation
response over the validation channel. response over the validation channel.
The association of challenges to identifiers is typically done by The association of challenges to identifiers is typically done by
requiring the client to perform some action that only someone who requiring the client to perform some action that only someone who
effectively controls the identifier can perform. For the challenges effectively controls the identifier can perform. For the challenges
in this document, the actions are: in this document, the actions are as follows:
o HTTP: Provision files under .well-known on a web server for the o HTTP: Provision files under .well-known on a web server for the
domain domain
o DNS: Provision DNS resource records for the domain o DNS: Provision DNS resource records for the domain
There are several ways that these assumptions can be violated, both There are several ways that these assumptions can be violated, both
by misconfiguration and by attacks. For example, on a web server by misconfiguration and by attacks. For example, on a web server
that allows non-administrative users to write to .well-known, any that allows non-administrative users to write to .well-known, any
user can claim to own the web server's hostname by responding to an user can claim to own the web server's hostname by responding to an
HTTP challenge. Similarly, if a server that can be used for ACME HTTP challenge. Similarly, if a server that can be used for ACME
skipping to change at page 80, line 42 skipping to change at page 82, line 42
query to a remote server of the attacker's choosing. There are a few query to a remote server of the attacker's choosing. There are a few
different mitigations that ACME servers can apply: different mitigations that ACME servers can apply:
o Always querying the DNS using a DNSSEC-validating resolver o Always querying the DNS using a DNSSEC-validating resolver
(enhancing security for zones that are DNSSEC-enabled) (enhancing security for zones that are DNSSEC-enabled)
o Querying the DNS from multiple vantage points to address local o Querying the DNS from multiple vantage points to address local
attackers attackers
o Applying mitigations against DNS off-path attackers, e.g., adding o Applying mitigations against DNS off-path attackers, e.g., adding
entropy to requests [I-D.vixie-dnsext-dns0x20] or only using TCP entropy to requests [DNS0x20] or only using TCP
Given these considerations, the ACME validation process makes it Given these considerations, the ACME validation process makes it
impossible for any attacker on the ACME channel or a passive attacker impossible for any attacker on the ACME channel or a passive attacker
on the validation channel to hijack the authorization process to on the validation channel to hijack the authorization process to
authorize a key of the attacker's choice. authorize a key of the attacker's choice.
An attacker that can only see the ACME channel would need to convince An attacker that can only see the ACME channel would need to convince
the validation server to provide a response that would authorize the the validation server to provide a response that would authorize the
attacker's account key, but this is prevented by binding the attacker's account key, but this is prevented by binding the
validation response to the account key used to request challenges. A validation response to the account key used to request challenges. A
skipping to change at page 83, line 12 skipping to change at page 85, line 12
* Is the name on the Public Suffix List? * Is the name on the Public Suffix List?
* Is the name a high-value name? * Is the name a high-value name?
* Is the name a known phishing domain? * Is the name a known phishing domain?
o Is the key in the CSR sufficiently strong? o Is the key in the CSR sufficiently strong?
o Is the CSR signed with an acceptable algorithm? o Is the CSR signed with an acceptable algorithm?
o Has issuance been authorized or forbidden by a Certificate o Has issuance been authorized or forbidden by a Certification
Authority Authorization (CAA) record? [RFC6844] Authority Authorization (CAA) record ([RFC6844])?
CAs that use ACME to automate issuance will need to ensure that their CAs that use ACME to automate issuance will need to ensure that their
servers perform all necessary checks before issuing. servers perform all necessary checks before issuing.
CAs using ACME to allow clients to agree to terms of service should CAs using ACME to allow clients to agree to terms of service should
keep in mind that ACME clients can automate this agreement, possibly keep in mind that ACME clients can automate this agreement, possibly
not involving a human user. not involving a human user.
ACME does not specify how the server constructs the URLs that it uses ACME does not specify how the server constructs the URLs that it uses
to address resources. If the server operator uses URLs that are to address resources. If the server operator uses URLs that are
predictable to third parties, this can leak information about what predictable to third parties, this can leak information about what
URLs exist on the server, since an attacker can probe for whether URLs exist on the server, since an attacker can probe for whether a
POST-as-GET request to the URL returns "Not Found" or "Unauthorized". POST-as-GET request to the URL returns 404 (Not Found) or 401
(Unauthorized).
For example, suppose that the CA uses highly structured URLs with For example, suppose that the CA uses highly structured URLs with
guessable fields: guessable fields:
o Accounts: https://example.com/:accountID o Accounts: https://example.com/:accountID
o Orders: https://example.com/:accountID/:domainName o Orders: https://example.com/:accountID/:domainName
o Authorizations: https://example.com/:accountID/:domainName o Authorizations: https://example.com/:accountID/:domainName
skipping to change at page 84, line 15 skipping to change at page 86, line 25
o Certificates: https://example.com/cert/:certID o Certificates: https://example.com/cert/:certID
Such a scheme would leak only the type of resource, hiding the Such a scheme would leak only the type of resource, hiding the
additional correlations revealed in the example above. additional correlations revealed in the example above.
11. Operational Considerations 11. Operational Considerations
There are certain factors that arise in operational reality that There are certain factors that arise in operational reality that
operators of ACME-based CAs will need to keep in mind when operators of ACME-based CAs will need to keep in mind when
configuring their services. For example: configuring their services. See the subsections below for examples.
11.1. Key Selection 11.1. Key Selection
ACME relies on two different classes of key pair: ACME relies on two different classes of key pair:
o Account key pairs, which are used to authenticate account holders o Account key pairs, which are used to authenticate account holders
o Certificate key pairs, which are used to sign and verify CSRs (and o Certificate key pairs, which are used to sign and verify CSRs (and
whose public keys are included in certificates) whose public keys are included in certificates)
Compromise of the private key of an account key pair has more serious Compromise of the private key of an account key pair has more serious
consequences than compromise of a private key corresponding to a consequences than compromise of a private key corresponding to a
certificate. While the compromise of a certificate key pair allows certificate. While the compromise of a certificate key pair allows
the attacker to impersonate the entities named in the certificate for the attacker to impersonate the entities named in the certificate for
the lifetime of the certificate, the compromise of an account key the lifetime of the certificate, the compromise of an account key
pair allows the attacker to take full control of the victim's ACME pair allows the attacker to take full control of the victim's ACME
account, and take any action that the legitimate account holder could account and take any action that the legitimate account holder could
take within the scope of ACME: take within the scope of ACME:
1. Issuing certificates using existing authorizations 1. Issuing certificates using existing authorizations
2. Revoking existing certificates 2. Revoking existing certificates
3. Accessing and changing account information (e.g., contacts) 3. Accessing and changing account information (e.g., contacts)
4. Changing the account key pair for the account, locking out the 4. Changing the account key pair for the account, locking out the
legitimate account holder legitimate account holder
For this reason, it is RECOMMENDED that each account key pair be used For this reason, it is RECOMMENDED that each account key pair be used
only for authentication of a single ACME account. For example, the only for authentication of a single ACME account. For example, the
public key of an account key pair MUST NOT be included in a public key of an account key pair MUST NOT be included in a
certificate. If an ACME client receives a request from a user for certificate. If an ACME client receives a request from a user for
account creation or key roll-over using an account key that the account creation or key rollover using an account key that the client
client knows to be used elsewhere, then the client MUST return an knows to be used elsewhere, then the client MUST return an error.
error. Clients MUST generate a fresh account key for every account Clients MUST generate a fresh account key for every account creation
creation or roll-over operation. Note that given the requirements of or rollover operation. Note that given the requirements of
Section 7.3.1, servers will not create accounts with reused keys Section 7.3.1, servers will not create accounts with reused keys
anyway. anyway.
ACME clients and servers MUST verify that a CSR submitted in a ACME clients and servers MUST verify that a CSR submitted in a
finalize request does not contain a public key for any known account finalize request does not contain a public key for any known account
key pair. In particular, when a server receives a finalize request, key pair. In particular, when a server receives a finalize request,
it MUST verify that the public key in a CSR is not the same as the it MUST verify that the public key in a CSR is not the same as the
public key of the account key pair used to authenticate that request. public key of the account key pair used to authenticate that request.
This assures that vulnerabilities in the protocols with which the This assures that vulnerabilities in the protocols with which the
certificate is used (e.g., signing oracles in TLS [JSS15]) do not certificate is used (e.g., signing oracles in TLS [JSS15]) do not
result in compromise of the ACME account. Because ACME accounts are result in compromise of the ACME account. Because ACME accounts are
uniquely identified by their account key pair (see Section 7.3.1) the uniquely identified by their account key pair (see Section 7.3.1),
server MUST not allow account key pair reuse across multiple the server MUST not allow account key pair reuse across multiple
accounts. accounts.
11.2. DNS security 11.2. DNS Security
As noted above, DNS forgery attacks against the ACME server can As noted above, DNS forgery attacks against the ACME server can
result in the server making incorrect decisions about domain control result in the server making incorrect decisions about domain control
and thus mis-issuing certificates. Servers SHOULD perform DNS and thus mis-issuing certificates. Servers SHOULD perform DNS
queries over TCP, which provides better resistance to some forgery queries over TCP, which provides better resistance to some forgery
attacks than DNS over UDP. attacks than DNS over UDP.
An ACME-based CA will often need to make DNS queries, e.g., to An ACME-based CA will often need to make DNS queries, e.g., to
validate control of DNS names. Because the security of such validate control of DNS names. Because the security of such
validations ultimately depends on the authenticity of DNS data, every validations ultimately depends on the authenticity of DNS data, every
possible precaution should be taken to secure DNS queries done by the possible precaution should be taken to secure DNS queries done by the
CA. It is therefore RECOMMENDED that ACME-based CAs make all DNS CA. Therefore, it is RECOMMENDED that ACME-based CAs make all DNS
queries via DNSSEC-validating stub or recursive resolvers. This queries via DNSSEC-validating stub or recursive resolvers. This
provides additional protection to domains which choose to make use of provides additional protection to domains that choose to make use of
DNSSEC. DNSSEC.
An ACME-based CA must use only a resolver if it trusts the resolver An ACME-based CA must only use a resolver if it trusts the resolver
and every component of the network route by which it is accessed. It and every component of the network route by which it is accessed.
is therefore RECOMMENDED that ACME-based CAs operate their own Therefore, it is RECOMMENDED that ACME-based CAs operate their own
DNSSEC-validating resolvers within their trusted network and use DNSSEC-validating resolvers within their trusted network and use
these resolvers both for both CAA record lookups and all record these resolvers both for CAA record lookups and all record lookups in
lookups in furtherance of a challenge scheme (A, AAAA, TXT, etc.). furtherance of a challenge scheme (A, AAAA, TXT, etc.).
11.3. Token Entropy 11.3. Token Entropy
The http-01 and dns-01 validation methods mandate the usage of a The http-01 and dns-01 validation methods mandate the use of a random
random token value to uniquely identify the challenge. The value of token value to uniquely identify the challenge. The value of the
the token is required to contain at least 128 bits of entropy for the token is required to contain at least 128 bits of entropy for the
following security properties. First, the ACME client should not be following security properties. First, the ACME client should not be
able to influence the ACME server's choice of token as this may allow able to influence the ACME server's choice of token as this may allow
an attacker to reuse a domain owner's previous challenge responses an attacker to reuse a domain owner's previous challenge responses
for a new validation request. Secondly, the entropy requirement for a new validation request. Second, the entropy requirement makes
makes it more difficult for ACME clients to implement a "naive" it more difficult for ACME clients to implement a "naive" validation
validation server that automatically replies to challenges without server that automatically replies to challenges without being
being configured per-challenge. configured per challenge.
11.4. Malformed Certificate Chains 11.4. Malformed Certificate Chains
ACME provides certificate chains in the widely-used format known ACME provides certificate chains in the widely used format known
colloquially as PEM (though it may diverge from the actual Privacy colloquially as PEM (though it may diverge from the actual Privacy
Enhanced Mail specifications [RFC1421], as noted in [RFC7468]). Some Enhanced Mail specification [RFC1421], as noted in [RFC7468]). Some
current software will allow the configuration of a private key and a current software will allow the configuration of a private key and a
certificate in one PEM file, by concatenating the textual encodings certificate in one PEM file by concatenating the textual encodings of
of the two objects. In the context of ACME, such software might be the two objects. In the context of ACME, such software might be
vulnerable to "key replacement" attacks. A malicious ACME server vulnerable to key replacement attacks. A malicious ACME server could
could cause a client to use a private key of its choosing by cause a client to use a private key of its choosing by including the
including the key in the PEM file returned in response to a query for key in the PEM file returned in response to a query for a certificate
a certificate URL. URL.
When processing a file of type "application/pem-certificate-chain", a When processing a file of type "application/pem-certificate-chain", a
client SHOULD verify that the file contains only encoded client SHOULD verify that the file contains only encoded
certificates. If anything other than a certificate is found (i.e., certificates. If anything other than a certificate is found (i.e.,
if the string "-----BEGIN" is ever followed by anything other than if the string "-----BEGIN" is ever followed by anything other than
"CERTIFICATE"), then the client MUST reject the file as invalid. "CERTIFICATE"), then the client MUST reject the file as invalid.
12. Acknowledgements 12. References
In addition to the editors listed on the front page, this document
has benefited from contributions from a broad set of contributors,
all the way back to its inception.
o Andrew Ayer, SSLMate
o Karthik Bhargavan, INRIA
o Peter Eckersley, EFF
o Alex Halderman, University of Michigan
o Sophie Herold, Hemio
o Eric Rescorla, Mozilla
o Seth Schoen, EFF
o Martin Thomson, Mozilla
o Jakub Warmuz, University of Oxford
This document draws on many concepts established by Eric Rescorla's
"Automated Certificate Issuance Protocol" draft. Martin Thomson
provided helpful guidance in the use of HTTP.
13. References
13.1. Normative References 12.1. Normative References
[FIPS180-4] [FIPS180-4]
Department of Commerce, National., "NIST FIPS 180-4, National Institute of Standards and Technology (NIST),
Secure Hash Standard", March 2012, "Secure Hash Standard (SHS)", FIPS PUB 180-4,
DOI 10.6028/NIST.FIPS.180-4, August 2015,
<http://csrc.nist.gov/publications/fips/fips180-4/ <http://csrc.nist.gov/publications/fips/fips180-4/
fips-180-4.pdf>. fips-180-4.pdf>.
[JSS15] Somorovsky, J., "On the Security of TLS 1.3 and QUIC [JSS15] Somorovsky, J., Schwenk, J., and J. Somorovsky, "On the
Against Weaknesses in PKCS#1 v1.5 Encryption", n.d., Security of TLS 1.3 and QUIC Against Weaknesses in PKCS#1
v1.5 Encryption", CSS '15 Proceedings of the 22nd ACM
SIGSAC Conference on Computer and Communications
Security Pages 1185-1196, DOI 10.1145/2810103.2813657,
<https://dl.acm.org/citation.cfm?id=2813657>. <https://dl.acm.org/citation.cfm?id=2813657>.
[REST] Fielding, R., "Architectural Styles and the Design of
Network-based Software Architectures", 2000,
<http://www.ics.uci.edu/~fielding/pubs/dissertation/
top.htm>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key [RFC2585] Housley, R. and P. Hoffman, "Internet X.509 Public Key
Infrastructure Operational Protocols: FTP and HTTP", Infrastructure Operational Protocols: FTP and HTTP",
RFC 2585, DOI 10.17487/RFC2585, May 1999, RFC 2585, DOI 10.17487/RFC2585, May 1999,
<https://www.rfc-editor.org/info/rfc2585>. <https://www.rfc-editor.org/info/rfc2585>.
skipping to change at page 88, line 32 skipping to change at page 90, line 14
[RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006, Encodings", RFC 4648, DOI 10.17487/RFC4648, October 2006,
<https://www.rfc-editor.org/info/rfc4648>. <https://www.rfc-editor.org/info/rfc4648>.
[RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax [RFC5234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", STD 68, RFC 5234, Specifications: ABNF", STD 68, RFC 5234,
DOI 10.17487/RFC5234, January 2008, DOI 10.17487/RFC5234, January 2008,
<https://www.rfc-editor.org/info/rfc5234>. <https://www.rfc-editor.org/info/rfc5234>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>. <https://www.rfc-editor.org/info/rfc5280>.
[RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet [RFC5751] Ramsdell, B. and S. Turner, "Secure/Multipurpose Internet
Mail Extensions (S/MIME) Version 3.2 Message Mail Extensions (S/MIME) Version 3.2 Message
Specification", RFC 5751, DOI 10.17487/RFC5751, January Specification", RFC 5751, DOI 10.17487/RFC5751, January
2010, <https://www.rfc-editor.org/info/rfc5751>. 2010, <https://www.rfc-editor.org/info/rfc5751>.
[RFC5890] Klensin, J., "Internationalized Domain Names for [RFC5890] Klensin, J., "Internationalized Domain Names for
Applications (IDNA): Definitions and Document Framework", Applications (IDNA): Definitions and Document Framework",
RFC 5890, DOI 10.17487/RFC5890, August 2010, RFC 5890, DOI 10.17487/RFC5890, August 2010,
<https://www.rfc-editor.org/info/rfc5890>. <https://www.rfc-editor.org/info/rfc5890>.
[RFC5988] Nottingham, M., "Web Linking", RFC 5988,
DOI 10.17487/RFC5988, October 2010,
<https://www.rfc-editor.org/info/rfc5988>.
[RFC6068] Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto' [RFC6068] Duerst, M., Masinter, L., and J. Zawinski, "The 'mailto'
URI Scheme", RFC 6068, DOI 10.17487/RFC6068, October 2010, URI Scheme", RFC 6068, DOI 10.17487/RFC6068, October 2010,
<https://www.rfc-editor.org/info/rfc6068>. <https://www.rfc-editor.org/info/rfc6068>.
[RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M., [RFC6570] Gregorio, J., Fielding, R., Hadley, M., Nottingham, M.,
and D. Orchard, "URI Template", RFC 6570, and D. Orchard, "URI Template", RFC 6570,
DOI 10.17487/RFC6570, March 2012, DOI 10.17487/RFC6570, March 2012,
<https://www.rfc-editor.org/info/rfc6570>. <https://www.rfc-editor.org/info/rfc6570>.
[RFC6844] Hallam-Baker, P. and R. Stradling, "DNS Certification [RFC6844] Hallam-Baker, P. and R. Stradling, "DNS Certification
Authority Authorization (CAA) Resource Record", RFC 6844, Authority Authorization (CAA) Resource Record", RFC 6844,
DOI 10.17487/RFC6844, January 2013, DOI 10.17487/RFC6844, January 2013,
<https://www.rfc-editor.org/info/rfc6844>. <https://www.rfc-editor.org/info/rfc6844>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>.
[RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer [RFC7231] Fielding, R., Ed. and J. Reschke, Ed., "Hypertext Transfer
Protocol (HTTP/1.1): Semantics and Content", RFC 7231, Protocol (HTTP/1.1): Semantics and Content", RFC 7231,
DOI 10.17487/RFC7231, June 2014, DOI 10.17487/RFC7231, June 2014,
<https://www.rfc-editor.org/info/rfc7231>. <https://www.rfc-editor.org/info/rfc7231>.
[RFC7468] Josefsson, S. and S. Leonard, "Textual Encodings of PKIX, [RFC7468] Josefsson, S. and S. Leonard, "Textual Encodings of PKIX,
PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468, PKCS, and CMS Structures", RFC 7468, DOI 10.17487/RFC7468,
April 2015, <https://www.rfc-editor.org/info/rfc7468>. April 2015, <https://www.rfc-editor.org/info/rfc7468>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web [RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
skipping to change at page 90, line 23 skipping to change at page 91, line 39
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>. May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[RFC8259] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", STD 90, RFC 8259,
DOI 10.17487/RFC8259, December 2017,
<https://www.rfc-editor.org/info/rfc8259>.
[RFC8288] Nottingham, M., "Web Linking", RFC 8288, [RFC8288] Nottingham, M., "Web Linking", RFC 8288,
DOI 10.17487/RFC8288, October 2017, DOI 10.17487/RFC8288, October 2017,
<https://www.rfc-editor.org/info/rfc8288>. <https://www.rfc-editor.org/info/rfc8288>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
13.2. Informative References 12.2. Informative References
[CABFBR] CA/Browser Forum, ., "CA/Browser Forum Baseline
Requirements", September 2018,
<https://cabforum.org/baseline-requirements-documents/>.
[I-D.ietf-acme-caa] [ACME-CAA]
Landau, H., "CAA Record Extensions for Account URI and Landau, H., "CAA Record Extensions for Account URI and
ACME Method Binding", draft-ietf-acme-caa-05 (work in ACME Method Binding", Work in Progress, draft-ietf-acme-
progress), June 2018. caa-06, January 2019.
[I-D.ietf-acme-ip] [ACME-IP] Shoemaker, R., "ACME IP Identifier Validation Extension",
Shoemaker, R., "ACME IP Identifier Validation Extension", Work in Progress, draft-ietf-acme-ip-05, February 2019.
draft-ietf-acme-ip-04 (work in progress), July 2018.
[I-D.ietf-acme-telephone] [ACME-TELEPHONE]
Peterson, J. and R. Barnes, "ACME Identifiers and Peterson, J. and R. Barnes, "ACME Identifiers and
Challenges for Telephone Numbers", draft-ietf-acme- Challenges for Telephone Numbers", Work in Progress,
telephone-01 (work in progress), October 2017. draft-ietf-acme-telephone-01, October 2017.
[I-D.vixie-dnsext-dns0x20] [CABFBR] CA/Browser Forum, "CA/Browser Forum Baseline
Vixie, P. and D. Dagon, "Use of Bit 0x20 in DNS Labels to Requirements", September 2018,
Improve Transaction Identity", draft-vixie-dnsext- <https://cabforum.org/baseline-requirements-documents/>.
dns0x20-00 (work in progress), March 2008.
[DNS0x20] Vixie, P. and D. Dagon, "Use of Bit 0x20 in DNS Labels to
Improve Transaction Identity", Work in Progress,
draft-vixie-dnsext-dns0x20-00, March 2008.
[RFC1421] Linn, J., "Privacy Enhancement for Internet Electronic [RFC1421] Linn, J., "Privacy Enhancement for Internet Electronic
Mail: Part I: Message Encryption and Authentication Mail: Part I: Message Encryption and Authentication
Procedures", RFC 1421, DOI 10.17487/RFC1421, February Procedures", RFC 1421, DOI 10.17487/RFC1421, February
1993, <https://www.rfc-editor.org/info/rfc1421>. 1993, <https://www.rfc-editor.org/info/rfc1421>.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552, Text on Security Considerations", BCP 72, RFC 3552,
DOI 10.17487/RFC3552, July 2003, DOI 10.17487/RFC3552, July 2003,
<https://www.rfc-editor.org/info/rfc3552>. <https://www.rfc-editor.org/info/rfc3552>.
skipping to change at page 91, line 24 skipping to change at page 92, line 42
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC [RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552, Text on Security Considerations", BCP 72, RFC 3552,
DOI 10.17487/RFC3552, July 2003, DOI 10.17487/RFC3552, July 2003,
<https://www.rfc-editor.org/info/rfc3552>. <https://www.rfc-editor.org/info/rfc3552>.
[RFC3553] Mealling, M., Masinter, L., Hardie, T., and G. Klyne, "An [RFC3553] Mealling, M., Masinter, L., Hardie, T., and G. Klyne, "An
IETF URN Sub-namespace for Registered Protocol IETF URN Sub-namespace for Registered Protocol
Parameters", BCP 73, RFC 3553, DOI 10.17487/RFC3553, June Parameters", BCP 73, RFC 3553, DOI 10.17487/RFC3553, June
2003, <https://www.rfc-editor.org/info/rfc3553>. 2003, <https://www.rfc-editor.org/info/rfc3553>.
[RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known [RFC5785] Nottingham, M. and E. Hammer-Lahav, "Defining Well-Known
Uniform Resource Identifiers (URIs)", RFC 5785, Uniform Resource Identifiers (URIs)", RFC 5785,
DOI 10.17487/RFC5785, April 2010, DOI 10.17487/RFC5785, April 2010,
<https://www.rfc-editor.org/info/rfc5785>. <https://www.rfc-editor.org/info/rfc5785>.
[RFC6960] Santesson, S., Myers, M., Ankney, R., Malpani, A.,
Galperin, S., and C. Adams, "X.509 Internet Public Key
Infrastructure Online Certificate Status Protocol - OCSP",
RFC 6960, DOI 10.17487/RFC6960, June 2013,
<https://www.rfc-editor.org/info/rfc6960>.
[RFC7132] Kent, S. and A. Chi, "Threat Model for BGP Path Security", [RFC7132] Kent, S. and A. Chi, "Threat Model for BGP Path Security",
RFC 7132, DOI 10.17487/RFC7132, February 2014, RFC 7132, DOI 10.17487/RFC7132, February 2014,
<https://www.rfc-editor.org/info/rfc7132>. <https://www.rfc-editor.org/info/rfc7132>.
[RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre, [RFC7525] Sheffer, Y., Holz, R., and P. Saint-Andre,
"Recommendations for Secure Use of Transport Layer "Recommendations for Secure Use of Transport Layer
Security (TLS) and Datagram Transport Layer Security Security (TLS) and Datagram Transport Layer Security
(DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May (DTLS)", BCP 195, RFC 7525, DOI 10.17487/RFC7525, May
2015, <https://www.rfc-editor.org/info/rfc7525>. 2015, <https://www.rfc-editor.org/info/rfc7525>.
[W3C.REC-cors-20140116] [W3C.REC-cors-20140116]
Kesteren, A., "Cross-Origin Resource Sharing", World Wide Kesteren, A., Ed., "Cross-Origin Resource Sharing", W3C
Web Consortium Recommendation REC-cors-20140116, January Recommendation REC-cors-20140116, January 2014,
2014, <http://www.w3.org/TR/2014/REC-cors-20140116>. <http://www.w3.org/TR/2014/REC-cors-20140116>.
13.3. URIs Acknowledgements
[1] https://github.com/ietf-wg-acme/acme In addition to the editors listed on the front page, this document
has benefited from contributions from a broad set of contributors,
all the way back to its inception.
[2] mailto:iesg@ietf.org o Andrew Ayer, SSLMate
o Karthik Bhargavan, INRIA
o Peter Eckersley, EFF
o Alex Halderman, University of Michigan
o Sophie Herold, Hemio
o Tim Hollebeek, DigiCert
o Eric Rescorla, Mozilla
o Seth Schoen, EFF
o Roland Shoemaker, Let's Encrypt
o Rob Stradling, Sectigo
o Martin Thomson, Mozilla
o Jakub Warmuz, University of Oxford
This document draws on many concepts established by Eric Rescorla's
"Automated Certificate Issuance Protocol" draft. Martin Thomson
provided helpful guidance in the use of HTTP.
Authors' Addresses Authors' Addresses
Richard Barnes Richard Barnes
Cisco Cisco
Email: rlb@ipv.sx Email: rlb@ipv.sx
Jacob Hoffman-Andrews Jacob Hoffman-Andrews
EFF EFF
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