draft-ietf-acme-acme-08.txt   draft-ietf-acme-acme-09.txt 
ACME Working Group R. Barnes ACME Working Group R. Barnes
Internet-Draft Cisco Internet-Draft Cisco
Intended status: Standards Track J. Hoffman-Andrews Intended status: Standards Track J. Hoffman-Andrews
Expires: May 3, 2018 EFF Expires: June 17, 2018 EFF
D. McCarney
Let's Encrypt
J. Kasten J. Kasten
University of Michigan University of Michigan
October 30, 2017 December 14, 2017
Automatic Certificate Management Environment (ACME) Automatic Certificate Management Environment (ACME)
draft-ietf-acme-acme-08 draft-ietf-acme-acme-09
Abstract Abstract
Certificates in PKI using X.509 (PKIX) are used for a number of Certificates in PKI using X.509 (PKIX) are used for a number of
purposes, the most significant of which is the authentication of purposes, the most significant of which is the authentication of
domain names. Thus, certificate authorities in the Web PKI are domain names. Thus, certificate authorities in the Web PKI are
trusted to verify that an applicant for a certificate legitimately trusted to verify that an applicant for a certificate legitimately
represents the domain name(s) in the certificate. Today, this represents the domain name(s) in the certificate. Today, this
verification is done through a collection of ad hoc mechanisms. This verification is done through a collection of ad hoc mechanisms. This
document describes a protocol that a certification authority (CA) and document describes a protocol that a certification authority (CA) and
an applicant can use to automate the process of verification and an applicant can use to automate the process of verification and
certificate issuance. The protocol also provides facilities for certificate issuance. The protocol also provides facilities for
other certificate management functions, such as certificate other certificate management functions, such as certificate
revocation. revocation.
DISCLAIMER: This is a work in progress draft of ACME and has not yet
had a thorough security analysis.
RFC EDITOR: PLEASE REMOVE THE FOLLOWING PARAGRAPH: The source for RFC EDITOR: PLEASE REMOVE THE FOLLOWING PARAGRAPH: The source for
this draft is maintained in GitHub. Suggested changes should be this draft is maintained in GitHub. Suggested changes should be
submitted as pull requests at https://github.com/ietf-wg-acme/acme . submitted as pull requests at https://github.com/ietf-wg-acme/acme
Instructions are on that page as well. Editorial changes can be [1]. Instructions are on that page as well. Editorial changes can
managed in GitHub, but any substantive change should be discussed on be managed in GitHub, but any substantive change should be discussed
the ACME mailing list (acme@ietf.org). 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 Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This Internet-Draft will expire on May 3, 2018. This Internet-Draft will expire on June 17, 2018.
Copyright Notice Copyright Notice
Copyright (c) 2017 IETF Trust and the persons identified as the Copyright (c) 2017 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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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 . . . . . . . . . . . . . . . . . . . . . . . . . 6 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7 4. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 7
5. Character Encoding . . . . . . . . . . . . . . . . . . . . . 8 5. Character Encoding . . . . . . . . . . . . . . . . . . . . . 9
6. Message Transport . . . . . . . . . . . . . . . . . . . . . . 9 6. Message Transport . . . . . . . . . . . . . . . . . . . . . . 9
6.1. HTTPS Requests . . . . . . . . . . . . . . . . . . . . . 9 6.1. HTTPS Requests . . . . . . . . . . . . . . . . . . . . . 9
6.2. Request Authentication . . . . . . . . . . . . . . . . . 10 6.2. Request Authentication . . . . . . . . . . . . . . . . . 10
6.3. Request URL Integrity . . . . . . . . . . . . . . . . . . 11 6.3. Request URL Integrity . . . . . . . . . . . . . . . . . . 11
6.3.1. "url" (URL) JWS header parameter . . . . . . . . . . 11 6.3.1. "url" (URL) JWS Header Parameter . . . . . . . . . . 12
6.4. Replay protection . . . . . . . . . . . . . . . . . . . . 12 6.4. Replay protection . . . . . . . . . . . . . . . . . . . . 12
6.4.1. Replay-Nonce . . . . . . . . . . . . . . . . . . . . 12 6.4.1. Replay-Nonce . . . . . . . . . . . . . . . . . . . . 12
6.4.2. "nonce" (Nonce) JWS header parameter . . . . . . . . 13 6.4.2. "nonce" (Nonce) JWS Header Parameter . . . . . . . . 13
6.5. Rate limits . . . . . . . . . . . . . . . . . . . . . . . 13 6.5. Rate Limits . . . . . . . . . . . . . . . . . . . . . . . 13
6.6. Errors . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.6. Errors . . . . . . . . . . . . . . . . . . . . . . . . . 13
7. Certificate Management . . . . . . . . . . . . . . . . . . . 15 6.6.1. Subproblems . . . . . . . . . . . . . . . . . . . . . 15
7.1. Resources . . . . . . . . . . . . . . . . . . . . . . . . 15 7. Certificate Management . . . . . . . . . . . . . . . . . . . 16
7.1.1. Directory . . . . . . . . . . . . . . . . . . . . . . 18 7.1. Resources . . . . . . . . . . . . . . . . . . . . . . . . 17
7.1.2. Account Objects . . . . . . . . . . . . . . . . . . . 19 7.1.1. Directory . . . . . . . . . . . . . . . . . . . . . . 19
7.1.3. Order Objects . . . . . . . . . . . . . . . . . . . . 20 7.1.2. Account Objects . . . . . . . . . . . . . . . . . . . 21
7.1.4. Authorization Objects . . . . . . . . . . . . . . . . 22 7.1.3. Order Objects . . . . . . . . . . . . . . . . . . . . 22
7.2. Getting a Nonce . . . . . . . . . . . . . . . . . . . . . 23 7.1.4. Authorization Objects . . . . . . . . . . . . . . . . 24
7.3. Account Creation . . . . . . . . . . . . . . . . . . . . 24 7.2. Getting a Nonce . . . . . . . . . . . . . . . . . . . . . 26
7.3.1. Finding an Account URL Given a Key . . . . . . . . . 26 7.3. Account Creation . . . . . . . . . . . . . . . . . . . . 27
7.3.2. Account Update . . . . . . . . . . . . . . . . . . . 27 7.3.1. Finding an Account URL Given a Key . . . . . . . . . 29
7.3.3. Account Information . . . . . . . . . . . . . . . . . 27 7.3.2. Account Update . . . . . . . . . . . . . . . . . . . 29
7.3.4. Changes of Terms of Service . . . . . . . . . . . . . 27 7.3.3. Account Information . . . . . . . . . . . . . . . . . 30
7.3.5. External Account Binding . . . . . . . . . . . . . . 28 7.3.4. Changes of Terms of Service . . . . . . . . . . . . . 30
7.3.6. Account Key Roll-over . . . . . . . . . . . . . . . . 30 7.3.5. External Account Binding . . . . . . . . . . . . . . 30
7.3.7. Account Deactivation . . . . . . . . . . . . . . . . 32 7.3.6. Account Key Roll-over . . . . . . . . . . . . . . . . 33
7.4. Applying for Certificate Issuance . . . . . . . . . . . . 33 7.3.7. Account Deactivation . . . . . . . . . . . . . . . . 35
7.4.1. Pre-Authorization . . . . . . . . . . . . . . . . . . 36 7.4. Applying for Certificate Issuance . . . . . . . . . . . . 36
7.4.2. Downloading the Certificate . . . . . . . . . . . . . 38 7.4.1. Pre-Authorization . . . . . . . . . . . . . . . . . . 40
7.5. Identifier Authorization . . . . . . . . . . . . . . . . 39 7.4.2. Downloading the Certificate . . . . . . . . . . . . . 42
7.5.1. Responding to Challenges . . . . . . . . . . . . . . 40 7.5. Identifier Authorization . . . . . . . . . . . . . . . . 43
7.5.2. Deactivating an Authorization . . . . . . . . . . . . 42 7.5.1. Responding to Challenges . . . . . . . . . . . . . . 44
7.6. Certificate Revocation . . . . . . . . . . . . . . . . . 43 7.5.2. Deactivating an Authorization . . . . . . . . . . . . 46
8. Identifier Validation Challenges . . . . . . . . . . . . . . 45 7.6. Certificate Revocation . . . . . . . . . . . . . . . . . 47
8.1. Key Authorizations . . . . . . . . . . . . . . . . . . . 47 8. Identifier Validation Challenges . . . . . . . . . . . . . . 49
8.2. Retrying Challenges . . . . . . . . . . . . . . . . . . . 47 8.1. Key Authorizations . . . . . . . . . . . . . . . . . . . 51
8.3. HTTP Challenge . . . . . . . . . . . . . . . . . . . . . 48 8.2. Retrying Challenges . . . . . . . . . . . . . . . . . . . 51
8.4. TLS with Server Name Indication (TLS SNI) Challenge . . . 50 8.3. HTTP Challenge . . . . . . . . . . . . . . . . . . . . . 52
8.5. DNS Challenge . . . . . . . . . . . . . . . . . . . . . . 52 8.4. TLS with Server Name Indication (TLS SNI) Challenge . . . 54
8.6. Out-of-Band Challenge . . . . . . . . . . . . . . . . . . 54 8.5. DNS Challenge . . . . . . . . . . . . . . . . . . . . . . 57
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 55 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 58
9.1. MIME Type: application/pem-certificate-chain . . . . . . 55 9.1. MIME Type: application/pem-certificate-chain . . . . . . 58
9.2. Well-Known URI for the HTTP Challenge . . . . . . . . . . 56 9.2. Well-Known URI for the HTTP Challenge . . . . . . . . . . 59
9.3. Replay-Nonce HTTP Header . . . . . . . . . . . . . . . . 56 9.3. Replay-Nonce HTTP Header . . . . . . . . . . . . . . . . 59
9.4. "url" JWS Header Parameter . . . . . . . . . . . . . . . 56 9.4. "url" JWS Header Parameter . . . . . . . . . . . . . . . 60
9.5. "nonce" JWS Header Parameter . . . . . . . . . . . . . . 57 9.5. "nonce" JWS Header Parameter . . . . . . . . . . . . . . 60
9.6. URN Sub-namespace for ACME (urn:ietf:params:acme) . . . . 57 9.6. URN Sub-namespace for ACME (urn:ietf:params:acme) . . . . 60
9.7. New Registries . . . . . . . . . . . . . . . . . . . . . 57 9.7. New Registries . . . . . . . . . . . . . . . . . . . . . 61
9.7.1. Fields in Account Objects . . . . . . . . . . . . . . 58 9.7.1. Fields in Account Objects . . . . . . . . . . . . . . 61
9.7.2. Fields in Order Objects . . . . . . . . . . . . . . . 59 9.7.2. Fields in Order Objects . . . . . . . . . . . . . . . 62
9.7.3. Error Types . . . . . . . . . . . . . . . . . . . . . 60 9.7.3. Fields in Authorization Objects . . . . . . . . . . . 63
9.7.4. Resource Types . . . . . . . . . . . . . . . . . . . 60 9.7.4. Error Types . . . . . . . . . . . . . . . . . . . . . 64
9.7.5. Identifier Types . . . . . . . . . . . . . . . . . . 61 9.7.5. Resource Types . . . . . . . . . . . . . . . . . . . 64
9.7.6. Validation Methods . . . . . . . . . . . . . . . . . 61 9.7.6. Fields in the "meta" Object within a Directory Object 65
10. Security Considerations . . . . . . . . . . . . . . . . . . . 63 9.7.7. Identifier Types . . . . . . . . . . . . . . . . . . 66
10.1. Threat model . . . . . . . . . . . . . . . . . . . . . . 63 9.7.8. Validation Methods . . . . . . . . . . . . . . . . . 66
10.2. Integrity of Authorizations . . . . . . . . . . . . . . 64 10. Security Considerations . . . . . . . . . . . . . . . . . . . 67
10.3. Denial-of-Service Considerations . . . . . . . . . . . . 66 10.1. Threat Model . . . . . . . . . . . . . . . . . . . . . . 68
10.4. Server-Side Request Forgery . . . . . . . . . . . . . . 67 10.2. Integrity of Authorizations . . . . . . . . . . . . . . 69
10.5. CA Policy Considerations . . . . . . . . . . . . . . . . 68 10.3. Denial-of-Service Considerations . . . . . . . . . . . . 71
11. Operational Considerations . . . . . . . . . . . . . . . . . 68 10.4. Server-Side Request Forgery . . . . . . . . . . . . . . 72
11.1. DNS security . . . . . . . . . . . . . . . . . . . . . . 69 10.5. CA Policy Considerations . . . . . . . . . . . . . . . . 72
11.2. Default Virtual Hosts . . . . . . . . . . . . . . . . . 69 11. Operational Considerations . . . . . . . . . . . . . . . . . 73
11.3. Token Entropy . . . . . . . . . . . . . . . . . . . . . 70 11.1. DNS security . . . . . . . . . . . . . . . . . . . . . . 73
11.4. Malformed Certificate Chains . . . . . . . . . . . . . . 70 11.2. Default Virtual Hosts . . . . . . . . . . . . . . . . . 74
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 71 11.3. Token Entropy . . . . . . . . . . . . . . . . . . . . . 75
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 71 11.4. Malformed Certificate Chains . . . . . . . . . . . . . . 75
13.1. Normative References . . . . . . . . . . . . . . . . . . 71 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 75
13.2. Informative References . . . . . . . . . . . . . . . . . 74 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 76
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 75 13.1. Normative References . . . . . . . . . . . . . . . . . . 76
13.2. Informative References . . . . . . . . . . . . . . . . . 78
13.3. URIs . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 80
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, certificate authorities in the Web authenticate domain names. Thus, certificate authorities in the Web
PKI are trusted to verify that an applicant for a certificate 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. For Validation" (DV) certificates are by far the most common type. For
DV validation, the CA merely verifies that the requester has DV validation, the CA merely verifies that the requester has
effective control of the web server and/or DNS server for the domain, effective control of the web server and/or DNS server for the domain,
but does not explicitly attempt to verify their real-world identity. but does not explicitly attempt to verify their real-world identity.
(This is as opposed to "Organization Validation" (OV) and "Extended (This is as opposed to "Organization Validation" (OV) and "Extended
Validation" (EV) certificates, where the process is intended to also Validation" (EV) certificates, where the process is intended to also
verify the real-world identity of the requester.) verify the real-world identity of the requester.)
Existing Web PKI certificate authorities tend to run on a set of ad Existing Web PKI certificate authorities tend to use a set of ad hoc
hoc protocols for certificate issuance and identity verification. In protocols for certificate issuance and identity verification. In the
the case of DV certificates, a typical user experience is something case of DV certificates, a typical user experience is something like:
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 web page. o Cut-and-paste the CSR into a CA web page.
o Prove ownership of the domain by one of the following methods: o Prove ownership of the domain 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 at a DNS location corresponding to * Put a CA-provided challenge in a DNS record corresponding to
the target domain. the target domain.
* Receive CA challenge at a (hopefully) administrator-controlled * Receive CA-provided challenge at a (hopefully) administrator-
email address corresponding to the domain and then respond to controlled email address corresponding to the domain and then
it on the CA's web page. 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 their 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 confusion. Informal usability tests to follow and cause significant confusion. Informal usability tests
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other protocols based on Transport Layer Security (TLS) [RFC5246]. other protocols based on Transport Layer Security (TLS) [RFC5246].
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 WebPKI certificates ongoing work to use ACME for issuance of WebPKI certificates
attesting to IP addresses [I-D.ietf-acme-ip] and STIR certificates attesting to IP addresses [I-D.ietf-acme-ip] and STIR certificates
attesting to telephone numbers [I-D.ietf-acme-telephone]. attesting to telephone numbers [I-D.ietf-acme-telephone].
ACME can also be used to automate some aspects of certificate
management even where non-automated processes are still needed. For
example, the external account binding feature (see Section 7.3.5) can
be used to associate authorizations with an account that were not
validated through the ACME authorization process. This allows ACME
to address issuance scenarios that cannot yet be fully automated,
such as the issuance of 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, the user's web server is intended (HTTPS [RFC2818]). In this case, the user's web server is intended
to speak for one or more domains, and the process of certificate to speak for one or more domains, and the process of certificate
issuance is intended to verify that this web server actually speaks issuance is intended to verify that this web server actually speaks
for the domain(s). for the 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 observed
by the certificate issuer in an interactive process that can be by the certificate issuer in an interactive process that can be
conducted purely online. That means that under typical 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, an operator typically Prior to ACME, when deploying an HTTPS server, a server operator
gets a prompt to generate a self-signed certificate. If the operator typically gets a prompt to generate a self-signed certificate. If
were instead deploying an HTTPS server using ACME, the experience the operator were instead deploying an HTTPS server using ACME, the
would be something like this: experience would be something like this:
o The ACME client prompts the operator for the intended domain o The operator's ACME client prompts the operator for the intended
name(s) that the web server is to stand for. domain name(s) that the web server is to stand for.
o The ACME client presents the operator with a list of CAs from o The ACME client presents the operator with a list of CAs from
which it could get a certificate. (This list will change over which it could get a certificate. (This list will change over
time based on the capabilities of CAs and updates to ACME time based on the capabilities of CAs and updates to ACME
configuration.) The ACME client might prompt the operator for configuration.) The ACME client might prompt the operator for
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). name(s) by having the ACME client perform some action related to
the domain name(s).
o Once the CA is satisfied, the certificate is issued 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 OCSP responses, or whatever else would be
required to keep the web server functional and its credentials up- required to keep the web server functional and its credentials up-
to-date. 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
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An ACME client is represented by an "account key pair". The client An ACME client is represented by an "account key pair". The client
uses the private key of this key pair to sign all messages sent to uses the private key of this key pair to sign all messages sent to
the server. The server uses the public key to verify the the server. The server uses the public key to verify the
authenticity and integrity of messages from the client. 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 carried over
HTTPS. In many ways, ACME functions much like a traditional CA, in HTTPS.
Issuance using ACME resembles a traditional CA's issuance process, in
which a user creates an account, requests a certificate, and proves which a user creates an account, requests a certificate, and proves
control of the domains in that certificate in order for the CA to control of the domains in that certificate in order for the CA to
sign the requested certificate. sign the requested 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, and/or associating the account with an
existing account in another system. The creation request is signed existing account in another system. The creation request is signed
with the generated private key to prove that the client controls it. with the generated private key to prove that the client controls it.
skipping to change at page 8, line 4 skipping to change at page 8, line 18
a certificate, it responds with a list of requirements that the a certificate, it responds with a list of requirements that the
client must satisfy before the certificate will be issued. client must satisfy before the certificate will be issued.
For example, in most cases, the server will require the client to For example, in most cases, the server will require the client to
demonstrate that it controls the identifiers in the requested demonstrate that it controls the identifiers in the requested
certificate. Because there are many different ways to validate certificate. Because there are many different ways to validate
possession of different types of identifiers, the server will choose possession of different types of identifiers, the server will choose
from an extensible set of challenges that are appropriate for the from an extensible set of challenges that are appropriate for the
identifier being claimed. The client responds with a set of identifier being claimed. The client responds with a set of
responses that tell the server which challenges the client has responses that tell the server which challenges the client has
completed. The server then validates the challenges to check that completed. The server then validates that the client has completed
the client has accomplished them. the challenges.
Once the validation process is complete and the server is satisfied Once the validation process is complete and the server is satisfied
that the client has met its requirements, the server will issue the that the client has met its requirements, the server will issue the
requested certificate and make it available to the client. requested certificate and make it available to the client.
Order Order
Signature -------> Signature ------->
Required <------- Required Authorizations
<------- Authorizations
Responses Responses
Signature -------> Signature ------->
<~~~~~~~~Validation~~~~~~~~> <~~~~~~~~Validation~~~~~~~~>
<------- Certificate <------- Certificate
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:
skipping to change at page 9, line 30 skipping to change at page 9, line 39
Section 7 below describes the message formats used by the function Section 7 below describes the message formats used by the function
and the order in which messages are sent. and the 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 an HTTP and HTTPS client when validating challenges via HTTP. as an HTTP and HTTPS client when validating challenges via HTTP.
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 (0xRTT). This is safe 1.3 MAY allow clients to send early data (0xRTT). This is safe
because the ACME protocol itself includes anti-replay protections. because the ACME protocol itself includes anti-replay protections
(see Section 6.4).
ACME clients SHOULD send a User-Agent header in accordance with ACME clients SHOULD send a User-Agent header in accordance with
[RFC7231], including the name and version of the ACME software in [RFC7231], including the name and version of the ACME software in
addition to the name and version of the underlying HTTP client addition to the name and version of the underlying HTTP client
software. software.
ACME clients SHOULD send an Accept-Language header in accordance with ACME clients SHOULD send an Accept-Language header in accordance with
[RFC7231] to enable localization of error messages. [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
skipping to change at page 11, line 35 skipping to change at page 11, line 45
against an intermediary changing the request URL to another ACME URL. against an intermediary changing the request URL to another ACME URL.
As noted in Section 6.2 above, all ACME request objects carry a "url" As noted in Section 6.2 above, 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. For these resources, with URLs provided to the client by the server. In requests sent to
the client MUST set the "url" header parameter to the exact string these resources, the client MUST set the "url" header parameter to
provided by the server (rather than performing any re-encoding on the the exact string provided by the server (rather than performing any
URL). The server SHOULD perform the corresponding string equality re-encoding on the URL). The server SHOULD perform the corresponding
check, configuring each resource with the URL string provided to string equality check, configuring each resource with the URL string
clients and having the resource check that requests have the same provided to clients and having the resource check that requests have
string in their "url" header parameter. the same string in their "url" header parameter.
6.3.1. "url" (URL) JWS header parameter 6.3.1. "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 URL. parameter MUST be a string representing the URL.
6.4. Replay protection 6.4. 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 requests have a mandatory anti-replay mechanism. This mechanism ACME requests have a mandatory anti-replay mechanism. This mechanism
skipping to change at page 13, line 12 skipping to change at page 13, line 18
according to the base64url encoding described in Section 2 of according to the base64url encoding described in Section 2 of
[RFC7515]. Clients MUST ignore invalid Replay-Nonce values. [RFC7515]. Clients MUST ignore invalid Replay-Nonce values.
base64url = [A-Z] / [a-z] / [0-9] / "-" / "_" base64url = [A-Z] / [a-z] / [0-9] / "-" / "_"
Replay-Nonce = *base64url Replay-Nonce = *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.
6.4.2. "nonce" (Nonce) JWS header parameter 6.4.2. "nonce" (Nonce) JWS Header Parameter
The "nonce" header parameter provides a unique value that enables the The "nonce" header parameter provides a unique value that enables the
verifier of a JWS to recognize when replay has occurred. The "nonce" verifier of a JWS to recognize when replay has occurred. The "nonce"
header parameter MUST be carried in the protected header of the JWS. header parameter MUST be carried in the protected header of the JWS.
The value of the "nonce" header parameter MUST be an octet string, The value of the "nonce" header parameter MUST be an octet string,
encoded according to the base64url encoding described in Section 2 of encoded according to the base64url encoding described in Section 2 of
[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.
6.5. Rate limits 6.5. Rate Limits
Creation of resources can be rate limited to ensure fair usage and Creation of resources can be rate limited by ACME servers to ensure
prevent abuse. Once the rate limit is exceeded, the server MUST fair usage and prevent abuse. Once the rate limit is exceeded, the
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 indicating when the current SHOULD send a "Retry-After" header indicating when the current
request may succeed again. If multiple rate limits are in place, request may succeed again. If multiple rate limits are in place,
that is the time where all rate limits allow access again for the that is the time where all rate limits allow access again for the
current request with exactly the same parameters. 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 tokens in the "Link" response, the server MAY send one or multiple link relations in the
header pointing to documentation about the specific hit rate limits "Link" header pointing to documentation about the specific rate limit
using the "urn:ietf:params:acme:documentation" relation. that was hit, using the "help" link relation type.
6.6. Errors 6.6. 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
"urn:ietf:params:acme:error:" namespace): "urn:ietf:params:acme:error:" namespace):
+-----------------------+-------------------------------------------+ +-------------------------+-----------------------------------------+
| Type | Description | | Type | Description |
+-----------------------+-------------------------------------------+ +-------------------------+-----------------------------------------+
| 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 |
| | | | | |
| badSignatureAlgorithm | The JWS was signed with an algorithm the | | badSignatureAlgorithm | The JWS was signed with an algorithm |
| | server does not support | | | the server does not support |
| | | | | |
| invalidContact | A contact URL for an account was invalid | | invalidContact | A contact URL for an account was |
| | | | | invalid |
| unsupportedContact | A contact URL for an account used an | | | |
| | unsupported protocol scheme | | unsupportedContact | A contact URL for an account used an |
| | | | | unsupported protocol scheme |
| accountDoesNotExist | The request specified an account that | | | |
| | does not exist | | externalAccountRequired | The request must include a value for |
| | | | | the "externalAccountBinding" field |
| malformed | The request message was malformed | | | |
| | | | accountDoesNotExist | The request specified an account that |
| rateLimited | The request exceeds a rate limit | | | does not exist |
| | | | | |
| rejectedIdentifier | The server will not issue for the | | malformed | The request message was malformed |
| | identifier | | | |
| | | | rateLimited | The request exceeds a rate limit |
| serverInternal | The server experienced an internal error | | | |
| | | | rejectedIdentifier | The server will not issue for the |
| unauthorized | The client lacks sufficient authorization | | | identifier |
| | | | | |
| unsupportedIdentifier | Identifier is not supported, but may be | | serverInternal | The server experienced an internal |
| | in future | | | error |
| | | | | |
| userActionRequired | Visit the "instance" URL and take actions | | unauthorized | The client lacks sufficient |
| | specified there | | | authorization |
| | | | | |
| badRevocationReason | The revocation reason provided is not | | unsupportedIdentifier | Identifier is not supported, but may be |
| | allowed by the server | | | in future |
| | | | | |
| caa | Certification Authority Authorization | | userActionRequired | Visit the "instance" URL and take |
| | (CAA) records forbid the CA from issuing | | | actions specified there |
| | | | | |
| dns | There was a problem with a DNS query | | badRevocationReason | The revocation reason provided is not |
| | | | | allowed by the server |
| connection | The server could not connect to | | | |
| | validation target | | caa | Certification Authority Authorization |
| | | | | (CAA) records forbid the CA from |
| tls | The server received a TLS error during | | | issuing |
| | validation | | | |
| | | | dns | There was a problem with a DNS query |
| incorrectResponse | Response received didn't match the | | | |
| | challenge's requirements | | connection | The server could not connect to |
+-----------------------+-------------------------------------------+ | | validation target |
| | |
| tls | The server received a TLS error during |
| | validation |
| | |
| incorrectResponse | Response received didn't match the |
| | challenge's requirements |
+-------------------------+-----------------------------------------+
This list is not exhaustive. The server MAY return errors whose This list is not exhaustive. The server MAY return errors whose
"type" field is set to a URI other than those defined above. Servers "type" field is set to a URI other than those defined above. Servers
MUST NOT use the ACME URN [RFC3553] namespace for errors other than MUST NOT use the ACME URN [RFC3553] namespace for errors other than
the standard types. Clients SHOULD display the "detail" field of all the standard types. Clients SHOULD display the "detail" field of all
errors. errors.
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
example, an "error of type 'badCSR'" refers to an error document with
"type" value "urn:ietf:params:acme:error:badCSR".
6.6.1. Subproblems
Sometimes a CA may need to return multiple errors in response to a
request. Additionally, the CA may need to attribute errors to
specific identifiers. For instance, a new-order request may contain
multiple identifiers for which the CA cannot issue. In this
situation, an ACME problem document MAY contain the "subproblems"
field, containing a JSON array of problem documents, each of which
MAY contain an "identifier" field. If present, the "identifier"
field MUST contain an ACME identifier (Section 9.7.7). The
"identifier" field MUST NOT be present at the top level in ACME
problem documents. It can only be present in subproblems.
Subproblems need not all have the same type, and do not need to match
the top level type.
ACME clients may choose to use the "identifier" field of a subproblem
as a hint that an operation would succeed if that identifier were
omitted. For instance, if an order contains ten DNS identifiers, and
the new-order request returns a problem document with two
subproblems, referencing two of those identifiers, the ACME client
may choose to submit another order containing only the eight
identifiers not listed in the problem document.
HTTP/1.1 403 Forbidden
Content-Type: application/problem+json
{
"type": "urn:ietf:params:acme:error:malformed",
"detail": "Some of the identifiers requested were rejected",
"subproblems": [
{
"type": "urn:ietf:params:acme:error:malformed",
"detail": "Invalid underscore in DNS name \"_example.com\"",
"identifier": {
"type": "dns",
"value": "_example.com"
}
},
{
"type": "urn:ietf:params:acme:error:rejectedIdentifier",
"detail": "This CA will not issue for \"example.net\"",
"identifier": {
"type": "dns",
"value": "example.net"
}
}
]
}
7. Certificate Management 7. Certificate Management
In this section, we describe the certificate management functions In this section, we describe the certificate management functions
that ACME enables: that ACME enables:
o Account Creation o Account Creation
o Ordering a Certificate o Ordering a Certificate
o Identifier Authorization o Identifier Authorization
skipping to change at page 16, line 10 skipping to change at page 17, line 27
to act for an identifier (Section 7.1.4) to act for an identifier (Section 7.1.4)
o Challenge resources, representing a challenge to prove control of o Challenge resources, representing a challenge to prove control of
an identifier (Section 7.5, Section 8) an identifier (Section 7.5, Section 8)
o Certificate resources, representing issued certificates o Certificate resources, representing issued certificates
(Section 7.4.2) (Section 7.4.2)
o A "directory" resource (Section 7.1.1) o A "directory" resource (Section 7.1.1)
o A "new-nonce" resource (Section 7.2) o A "newNonce" resource (Section 7.2)
o A "new-account" resource (Section 7.3) o A "newAccount" resource (Section 7.3)
o A "new-order" resource (Section 7.4) o A "newOrder" resource (Section 7.4)
o A "revoke-cert" resource (Section 7.6) o A "revokeCert" resource (Section 7.6)
o A "key-change" resource (Section 7.3.6) o A "keyChange" resource (Section 7.3.6)
The server MUST provide "directory" and "new-nonce" 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 [RFC5988].
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 from certificate resources to indicate a resource from which the used from certificate resources to indicate a resource from which the
client may fetch a chain of CA certificates that could be used to client may fetch a chain of CA certificates that could be used to
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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.
The following diagram illustrates the relations between resources on The following diagram illustrates the relations between resources on
an ACME server. For the most part, these relations are expressed by an ACME server. For the most part, these relations are expressed by
URLs provided as strings in the resources' JSON representations. URLs provided as strings in the resources' JSON representations.
Lines with labels in quotes indicate HTTP link relations. Lines with labels in quotes indicate HTTP link relations.
directory directory
| |
|--> new-nonce +--> new-nonce
| |
----------------------------------+ +----------+----------+-----+-----+------------+
| | | | | | | | |
| | | | | | | | |
V V V V V V V V V
new-account new-authz new-order revoke-cert newAccount newAuthz newOrder revokeCert keyChange
| | | | | |
| | | | | |
V | V V | V
account | order -----> cert account | order -----> cert
| | | |
| | | |
| V | V
+------> authz +------> authz
| ^ | ^
| | "up" | | "up"
V | V |
challenge challenge
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 pointing to a created resource.
+----------------------+------------------+----------------+ +----------------------+---------------------+----------------+
| Action | Request | Response | | Action | Request | Response |
+----------------------+------------------+----------------+ +----------------------+---------------------+----------------+
| Get a nonce | HEAD new-nonce | 204 | | Get a nonce | HEAD newNonce | 204 |
| | | | | | | |
| Create account | POST new-account | 201 -> account | | Create account | POST newAccount | 201 -> account |
| | | | | | | |
| Submit an order | POST new-order | 201 -> order | | Submit an order | POST newOrder | 201 -> order |
| | | | | | | |
| Fetch challenges | GET authz | 200 | | Fetch challenges | GET authz | 200 |
| | | | | | | |
| Respond to challenge | POST challenge | 200 | | Respond to challenge | POST challenge | 200 |
| | | | | | | |
| Poll for status | GET authz | 200 | | Finalize order | POST order finalize | 200 |
| | | | | | | |
| Check for new cert | GET cert | 200 | | Poll for status | GET authz | 200 |
+----------------------+------------------+----------------+ | | | |
| Check for new cert | GET cert | 200 |
+----------------------+---------------------+----------------+
The remainder of this section provides the details of how these The remainder of this section provides the details of how these
resources are structured and how the ACME protocol makes use of them. resources are structured and how the ACME protocol makes use of them.
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 fields names are drawn from the following table and object, whose field names are drawn from the following table and
whose values are the corresponding URLs. whose values are the corresponding URLs.
+-------------+--------------------+ +------------+--------------------+
| Field | URL in value | | Field | URL in value |
+-------------+--------------------+ +------------+--------------------+
| new-nonce | New nonce | | newNonce | New nonce |
| | | | | |
| new-account | New account | | newAccount | New account |
| | | | | |
| new-order | New order | | newOrder | New order |
| | | | | |
| new-authz | New authorization | | newAuthz | New authorization |
| | | | | |
| revoke-cert | Revoke certificate | | revokeCert | Revoke certificate |
| | | | | |
| key-change | Key change | | keyChange | Key change |
+-------------+--------------------+ +------------+--------------------+
There is no constraint on the actual URL of the directory except that There is no constraint on the URL of the directory except that it
it should be different from the other ACME server resources' URLs, should be different from the other ACME server resources' URLs, and
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 which functions as both an ACME and a Web server may want
to keep the root path "/" for an HTML "front page", and place the to keep the root path "/" for an HTML "front page", and place the
ACME directory under the path "/acme". ACME directory under the path "/acme".
o a host which only functions as an ACME server could place the o a host which only functions as an ACME server could place the
directory under the path "/". directory under the path "/".
The object MAY additionally contain a field "meta". If present, it The object MAY additionally contain a field "meta". 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, all of which are OPTIONAL: The following metadata items are defined, all of which are OPTIONAL:
"terms-of-service" (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 (optional, string): An HTTP or HTTPS URL locating a website
website providing more information about the ACME server. providing more information about the ACME server.
"caa-identities" (optional, array of string): Each string MUST be a caaIdentities (optional, array of string): Each string MUST be a
lowercase hostname which the ACME server recognizes as referring lowercase hostname which the ACME server recognizes as referring
to itself for the purposes of CAA record validation as defined in to itself for the purposes of CAA record validation as defined in
[RFC6844]. This allows clients to determine the correct issuer [RFC6844]. This allows clients to determine the correct issuer
domain name to use when configuring CAA records. domain name to use when configuring CAA records.
externalAccountRequired (optional, boolean): If this field is
present and set to "true", then the CA requires that all new-
account requests include an "externalAccountBinding" field
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
{ {
"new-nonce": "https://example.com/acme/new-nonce", "newNonce": "https://example.com/acme/new-nonce",
"new-account": "https://example.com/acme/new-account", "newAccount": "https://example.com/acme/new-account",
"new-order": "https://example.com/acme/new-order", "newOrder": "https://example.com/acme/new-order",
"new-authz": "https://example.com/acme/new-authz", "newAuthz": "https://example.com/acme/new-authz",
"revoke-cert": "https://example.com/acme/revoke-cert", "revokeCert": "https://example.com/acme/revoke-cert",
"key-change": "https://example.com/acme/key-change", "keyChange": "https://example.com/acme/key-change",
"meta": { "meta": {
"terms-of-service": "https://example.com/acme/terms/2017-5-30", "termsOfService": "https://example.com/acme/terms/2017-5-30",
"website": "https://www.example.com/", "website": "https://www.example.com/",
"caa-identities": ["example.com"] "caaIdentities": ["example.com"],
"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. initiated deactivation.
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. about server-initiated revocation or certificate expiration.
terms-of-service-agreed (optional, boolean): Including this field in termsOfServiceAgreed (optional, boolean): Including this field in a
a new-account request, with a value of true, indicates the new-account request, with a value of true, indicates the client's
client's agreement with the terms of service. This field is not agreement with the terms of service. This field is not updateable
updateable by the client. by the client.
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 GET request, as submitted by this account can be fetched via a GET request, as
described in Section 7.1.2.1. described in Section 7.1.2.1.
{ {
"status": "valid", "status": "valid",
"contact": [ "contact": [
"mailto:cert-admin@example.com", "mailto:cert-admin@example.com",
"tel:+12025551212" "mailto:admin@example.com"
], ],
"terms-of-service-agreed": true, "termsOfServiceAgreed": true,
"orders": "https://example.com/acme/acct/1/orders" "orders": "https://example.com/acme/acct/1/orders"
} }
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 GET request. The orders created by the account can be fetched via GET request. The
result of the GET request MUST be a JSON object whose "orders" field result of the GET 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 with a "next" return an incomplete list, along with a Link header with a "next"
link relation indicating where further entries can be acquired. link relation indicating where further entries can be acquired.
HTTP/1.1 200 OK HTTP/1.1 200 OK
Content-Type: application/json Content-Type: application/json
Link: href="/acme/acct/1/orders?cursor=2", rel="next" Link: <https://example.com/acme/acct/1/orders?cursor=2>, rel="next"
{ {
"orders": [ "orders": [
"https://example.com/acme/acct/1/order/1", "https://example.com/acme/acct/1/order/1",
"https://example.com/acme/acct/1/order/2", "https://example.com/acme/acct/1/order/2",
/* 47 more URLs not shown for example brevity */ /* 47 more URLs not shown for example brevity */
"https://example.com/acme/acct/1/order/50" "https://example.com/acme/acct/1/order/50"
] ]
} }
skipping to change at page 21, line 10 skipping to change at page 23, line 7
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", "processing", "valid", and "invalid". values are: "pending", "processing", "valid", and "invalid".
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 RFC 3339 [RFC3339]. This field is REQUIRED for objects with
"pending" or "valid" in the status field. "pending" or "valid" in the status field.
csr (required, string): A CSR encoding the parameters for the identifiers (required, array of object): An array of identifier
certificate being requested [RFC2986]. The CSR is sent in the objects that the order pertains to.
base64url-encoded version of the DER format. (Note: Because this
field uses base64url, and does not include headers, it is type (required, string): The type of identifier.
different from PEM.)
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].
notAfter (optional, string): The requested value of the notAfter notAfter (optional, string): The requested value of the notAfter
field in the certificate, in the date format defined in [RFC3339]. field in the certificate, in the date format defined in [RFC3339].
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). For final requested certificate can be issued (see Section 7.5). For final
orders, the authorizations that were completed. Each entry is a orders (in the "valid" or "invalid" state), the authorizations
URL from which an authorization can be fetched with a GET request. that were completed. Each entry is a URL from which an
authorization can be fetched with a GET request.
finalize (requred, string): A URL that a CSR must be POSTed to once
all of the order's authorizations are satisfied to finalize the
order. The result of a successful finalization will be the
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": "pending", "status": "valid",
"expires": "2015-03-01T14:09:00Z", "expires": "2015-03-01T14:09:00Z",
"csr": "jcRf4uXra7FGYW5ZMewvV...rhlnznwy8YbpMGqwidEXfE", "identifiers": [
{ "type": "dns", "value": "example.com" },
{ "type": "dns", "value": "www.example.com" }
],
"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/1234", "https://example.com/acme/authz/1234",
"https://example.com/acme/authz/2345" "https://example.com/acme/authz/2345"
], ],
"finalize": "https://example.com/acme/acct/1/order/1/finalize",
"certificate": "https://example.com/acme/cert/1234" "certificate": "https://example.com/acme/cert/1234"
} }
The elements of the "authorizations" array are immutable once set. Any identifier of type "dns" in a new-order request MAY have a
The server MUST NOT change the contents of the "authorizations" array wildcard domain name as its value. A wildcard domain name consists
after it is created. If a client observes a change in the contents of a single asterisk character followed by a single full stop
of the "authorizations" array, then it SHOULD consider the order character ("_.") followed by a domain name as defined for use in the
invalid. Subject Alternate Name Extension by RFC 5280 . An authorization
returned by the server for a wildcard domain name identifier MUST NOT
include the asterisk and full stop ("_[RFC5280].") prefix in the
authorization identifier value.
The elements of the "authorizations" and "identifiers" array are
immutable once set. The server MUST NOT change the contents either
array after they are created. If a client observes a change in the
contents of either array, then it SHOULD consider the order invalid.
The "authorizations" array in the challenge SHOULD reflect all The "authorizations" array in the challenge 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,
then it SHOULD reflect that authorization in all of the orders. then it SHOULD reflect that authorization in all of the orders.
7.1.4. Authorization Objects 7.1.4. Authorization Objects
skipping to change at page 22, line 42 skipping to change at page 25, line 26
status (required, string): The status of this authorization. status (required, string): The status of this authorization.
Possible values are: "pending", "processing", "valid", "invalid" Possible values are: "pending", "processing", "valid", "invalid"
and "revoked". and "revoked".
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 RFC 3339 [RFC3339]. This field is REQUIRED for
objects with "valid" in the "status" field. objects with "valid" in the "status" field.
scope (optional, string): If this field is present, then it MUST
contain a URL for an order resource, such that this authorization
is only valid for that resource. If this field is absent, then
the CA MUST consider this authorization valid for all orders until
the authorization expires.
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 final authorizations, the possession of the identifier. For final authorizations (in the
challenges that were used. Each array entry is an object with "valid" or "invalid" state), the challenges that were used. Each
parameters required to validate the challenge. A client should array entry is an object with parameters required to validate the
attempt to fulfill one of these challenges, and a server should challenge. A client should attempt to fulfill one of these
consider any one of the challenges sufficient to make the challenges, and a server should consider any one of the challenges
authorization valid. For final authorizations, it contains the sufficient to make the authorization valid. For final
challenges that were successfully completed. authorizations, it contains the challenges that were successfully
completed.
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"). If a domain name contains non- qualified domain name (type: "dns"). If a domain name contains non-
ASCII Unicode characters it MUST be encoded using the rules defined ASCII Unicode characters it MUST be encoded using the rules defined
in [RFC3492]. Servers MUST verify any identifier values that begin in [RFC3492]. Servers MUST verify any identifier values that begin
with the ASCII Compatible Encoding prefix "xn-" as defined in with the ASCII Compatible Encoding prefix "xn-" as defined in
[RFC5890] are properly encoded. Wildcard domain names (with "*" as [RFC5890] are properly encoded. Wildcard domain names (with "*" as
the first label) MUST NOT be included in authorization objects. the first label) MUST NOT be included in authorization objects.
Section 8 describes a set of challenges for domain name validation. Section 8 describes a set of challenges for domain name validation.
skipping to change at page 23, line 31 skipping to change at page 26, line 16
"status": "valid", "status": "valid",
"expires": "2015-03-01T14:09:00Z", "expires": "2015-03-01T14:09:00Z",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.org" "value": "example.org"
}, },
"challenges": [ "challenges": [
{ {
"url": "https://example.com/authz/1234/0", "url": "https://example.com/acme/authz/1234/0",
"type": "http-01", "type": "http-01",
"status": "valid", "status": "valid",
"token": "DGyRejmCefe7v4NfDGDKfA" "token": "DGyRejmCefe7v4NfDGDKfA"
"validated": "2014-12-01T12:05:00Z", "validated": "2014-12-01T12:05:00Z",
"keyAuthorization": "SXQe-2XODaDxNR...vb29HhjjLPSggwiE" "keyAuthorization": "SXQe-2XODaDxNR...vb29HhjjLPSggwiE"
} }
] ]
} }
7.2. Getting a Nonce 7.2. Getting a Nonce
skipping to change at page 24, line 27 skipping to change at page 27, line 12
clients receive the same nonce repeatedly, leading to badNonce clients 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 new-nonce resource, in
order to prevent caching of this resource. order to prevent caching of this resource.
7.3. Account Creation 7.3. Account Creation
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 new-account URL. The body of the request is
a stub account object containing the "contact" field and optionally a stub account object containing the "contact" field and optionally
the "terms-of-service-agreed" field. the "termsOfServiceAgreed" field.
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
terms-of-service-agreed (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
only-return-existing (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).
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({
"terms-of-service-agreed": true, "termsOfServiceAgreed": true,
"contact": [ "contact": [
"mailto:cert-admin@example.com", "mailto:cert-admin@example.com",
"tel:+12025551212" "mailto:admin@example.com"
] ]
}), }),
"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 bodies 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.
skipping to change at page 26, line 7 skipping to change at page 28, line 27
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 describing the error and what types of contact URLs the
server considers acceptable. If the server rejects a contact URL for server considers acceptable. If the server rejects a contact URL for
using a supported scheme but an invalid value then the server MUST using a supported scheme but an invalid value then the server MUST
return an error of type "invalidContact". return an error of type "invalidContact".
If the server wishes to present the client with terms under which the If the server wishes to present the client with terms under which the
ACME service is to be used, it MUST indicate the URL where such terms ACME service is to be used, it MUST indicate the URL where such terms
can be accessed in the "terms-of-service" subfield of the "meta" can be accessed in the "termsOfService" subfield of the "meta" field
field in the directory object, and the server MUST reject new-account in the directory object, and the server MUST reject new-account
requests that do not have the "terms-of-service-agreed" set to requests that do not have the "termsOfServiceAgreed" set to "true".
"true". Clients SHOULD NOT automatically agree to terms by default. Clients SHOULD NOT automatically agree to terms by default. Rather,
Rather, they SHOULD require some user interaction for agreement to they SHOULD require some user interaction for agreement to terms.
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. in a Location header field.
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
Location: https://example.com/acme/acct/1 Location: https://example.com/acme/acct/1
Link: <https://example.com/acme/some-directory>;rel="index" Link: <https://example.com/acme/some-directory>;rel="index"
{ {
"status": "valid", "status": "valid",
"contact": [ "contact": [
"mailto:cert-admin@example.com", "mailto:cert-admin@example.com",
"tel:+12025551212" "mailto:admin@example.com"
] ]
} }
7.3.1. Finding an Account URL Given a Key 7.3.1. Finding an Account URL Given a Key
If the server already has an account registered with the provided If the server already has an account registered with the provided
account key, then it MUST return a response with a 200 (OK) status account key, then it MUST return a response with a 200 (OK) status
code and provide the URL of that account in the Location header code and provide the URL of that account in the Location header
field. This allows a client that has an account key but not the field. 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 new-account URL with
a JWS whose payload has an "only-return-existing" field set to "true" a JWS whose payload has an "onlyReturnExisting" field set to "true"
({"only-return-existing": true}). If a client sends such a request ({"onlyReturnExisting": true}). If a client sends such a request and
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.
The server MUST ignore any updates to "order" fields or any other The server MUST ignore any updates to "order" fields or any other
fields it does not recognize. If the server accepts the update, it fields it does not recognize. If the server accepts the update, it
MUST return a response with a 200 (OK) status code and the resulting MUST return a response with a 200 (OK) status code and the resulting
skipping to change at page 27, line 31 skipping to change at page 29, line 48
{ {
"protected": base64url({ "protected": base64url({
"alg": "ES256", "alg": "ES256",
"kid": "https://example.com/acme/acct/1", "kid": "https://example.com/acme/acct/1",
"nonce": "ax5RnthDqp_Yf4_HZnFLmA", "nonce": "ax5RnthDqp_Yf4_HZnFLmA",
"url": "https://example.com/acme/acct/1" "url": "https://example.com/acme/acct/1"
}), }),
"payload": base64url({ "payload": base64url({
"contact": [ "contact": [
"mailto:certificates@example.com", "mailto:certificates@example.com",
"tel:+12125551212" "mailto:admin@example.com"
] ]
}), }),
"signature": "hDXzvcj8T6fbFbmn...rDzXzzvzpRy64N0o" "signature": "hDXzvcj8T6fbFbmn...rDzXzzvzpRy64N0o"
} }
7.3.3. Account Information 7.3.3. Account Information
Servers SHOULD NOT respond to GET requests for account resources as Servers SHOULD NOT respond to GET requests for account resources as
these requests are not authenticated. If a client wishes to query these requests are not authenticated. If a client wishes to query
the server for information about its account (e.g., to examine the the server for information about its account (e.g., to examine the
"contact" or "certificates" fields), then it SHOULD do so by sending "contact" or "certificates" fields), then it SHOULD do so by sending
a POST request with an empty update. That is, it should send a JWS a POST request with an empty update. That is, it should send a JWS
whose payload is an empty object ({}). whose payload is an empty object ({}).
7.3.4. Changes of Terms of Service 7.3.4. 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 "terms-of-service-agreed" field in terms of service by setting the "termsOfServiceAgreed" field in its
its account object to "true". account object to "true".
If the server has changed its terms of service since a client If the server has changed its terms of service since a client
initially agreed, and the server is unwilling to process a request initially agreed, and the server is unwilling to process a request
without explicit agreement to the new terms, then it MUST return an without explicit agreement to the new terms, then it MUST return an
error response with status code 403 (Forbidden) and type error response with status code 403 (Forbidden) and type
"urn:ietf:params:acme:error:userActionRequired". This response MUST "urn:ietf:params:acme:error:userActionRequired". This response MUST
include a Link header with link relation "terms-of-service" and the include a Link header with link relation "terms-of-service" and the
latest terms-of-service URL. 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
skipping to change at page 28, line 27 skipping to change at page 30, line 42
HTTP/1.1 403 Forbidden HTTP/1.1 403 Forbidden
Replay-Nonce: IXVHDyxIRGcTE0VSblhPzw Replay-Nonce: IXVHDyxIRGcTE0VSblhPzw
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": "http://example.com/agreement/?token=W8Ih3PswD-8" "instance": "https://example.com/acme/agreement/?token=W8Ih3PswD-8"
} }
7.3.5. External Account Binding 7.3.5. External Account Binding
The server MAY require a value to be present for the "external- The server MAY require a value for the "externalAccountBinding" field
account-binding" field. This can be used to an ACME account with an to be present in "newAccount" requests. This can be used to
existing account in a non-ACME system, such as a CA customer associate an ACME account with an existing account in a non-ACME
database. system, such as a CA customer database.
To enable ACME account binding, a CA needs to provision the ACME To enable ACME account binding, a CA needs to provide the ACME client
client with a MAC key and a key identifier. The key identifier MUST with a MAC key and a key identifier, using some mechanism outside of
be an ASCII string. The MAC key SHOULD be provided in base64url- ACME. The key identifier MUST be an ASCII string. The MAC key
encoded form, to maximize compatibility between provisioning systems SHOULD be provided in base64url-encoded form, to maximize
and ACME clients. compatibility between non-ACME provisioning systems and ACME clients.
The ACME client then computes a binding JWS to indicate the external The ACME client then computes a binding JWS to indicate the external
account's approval of the ACME account key. The payload of this JWS account holder's approval of the ACME account key. The payload of
is the account key being registered, in JWK form. The protected this JWS is the account key being registered, in JWK form. The
header of the JWS MUST meet the following criteria: protected header of the JWS MUST meet the following criteria:
o The "alg" field MUST indicate a MAC-based algorithm o The "alg" field MUST indicate a MAC-based algorithm
o The "kid" field MUST contain the key identifier provided by the CA o The "kid" field MUST contain the key identifier provided by the CA
o The "nonce" field MUST NOT be present o The "nonce" field MUST NOT be present
o The "url" field MUST be set to the same value as the outer JWS o The "url" field MUST be set to the same value as the outer JWS
The "signature" field of the JWS will contain the MAC value computed The "signature" field of the JWS will contain the MAC value computed
with the MAC key provided by the CA. with the MAC key provided by the CA.
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
{ {
skipping to change at page 29, line 22 skipping to change at page 32, line 18
{ {
"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:example@anonymous.invalid"],
"terms-of-service-agreed": true, "termsOfServiceAgreed": true,
"external-account-binding": { "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"
} }
When a CA receives a new-account request containing an "external- If a CA requires that new-account requests contain an
account-binding" field, it decides whether or not to verify the "externalAccountBinding" field, then it MUST provide the value "true"
binding. If the CA does not verify the binding, then it MUST NOT in the "externalAccountRequired" subfield of the "meta" field in the
reflect the "external-account-binding" field in the resulting account directory object. If the CA receives a new-account request without
an "externalAccountBinding" field, then it should reply with an error
of type "externalAccountRequired".
When a CA receives a new-account request containing an
"externalAccountBinding" field, it decides whether or not to verify
the binding. If the CA does not verify the binding, then it MUST NOT
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 meets the above criteria 2. Verify that the JWS protected meets the above criteria
3. Retrieve the MAC key corresponding to the key identifier in the 3. Retrieve the MAC key corresponding to the key identifier in the
"kid" field "kid" field
skipping to change at page 30, line 4 skipping to change at page 33, line 6
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 meets the above criteria 2. Verify that the JWS protected meets the above criteria
3. Retrieve the MAC key corresponding to the key identifier in the 3. Retrieve the MAC key corresponding to the key identifier in the
"kid" field "kid" field
4. Verify that the MAC on the JWS verifies using that MAC key 4. Verify that the MAC on the JWS verifies using that MAC key
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 and MUST reflect value of the account corresponding to the MAC key and MUST reflect the value of
"external-account-binding" field in the resulting account object. If the "externalAccountBinding" field in the resulting account object.
any of these checks fail, then the CA MUST reject the new-account If any of these checks fail, then the CA MUST reject the new-account
request. request.
7.3.6. Account Key Roll-over 7.3.6. Account Key Roll-over
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 first To change the key associated with an account, the client first
constructs a key-change object describing the change that it would constructs a key-change object describing the change that it would
like the server to make: like the server to make:
account (required, string): The URL for account being modified. The account (required, string): The URL for account being modified. The
content of this field MUST be the exact string provided in 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 new-account request that
created the account. created the account.
newKey (required, JWK): The JWK representation of the new key newKey (required, JWK): The JWK representation of the new key
The client then encapsulates the key-change object in a JWS, signed The client then encapsulates the key-change object in an "inner" JWS,
with the requested new account key (i.e., the key matching the signed with the requested new account key (i.e., the key matching the
"newKey" value). "newKey" value). This JWS then becomes 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 (see
Section 6.2). The inner JWS MUST meet the normal requirements, with Section 6.2). The inner JWS MUST meet the normal requirements, with
the following exceptions: the following differences:
o The inner JWS MUST have a "jwk" header parameter, containing the
public key of the new key pair (i.e., the same value as the
"newKey" field).
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 is NOT REQUIRED to have a "nonce" header parameter. o The inner JWS is NOT REQUIRED to have a "nonce" header parameter.
The server MUST ignore any value provided for the "nonce" header The server MUST ignore any value provided for the "nonce" header
parameter. 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
that the server can verify that the holders of the two keys both that the server can verify that the holders of the two keys both
skipping to change at page 33, line 24 skipping to change at page 36, line 45
deactivated account. deactivated account.
7.4. Applying for Certificate Issuance 7.4. Applying for Certificate Issuance
The client requests certificate issuance by sending a POST request to The client requests certificate issuance by sending a POST request to
the server's new-order resource. The body of the POST is a JWS the server's new-order resource. The body of the POST is a JWS
object whose JSON payload is a subset of the order object defined in object whose JSON payload is a subset of the order object defined in
Section 7.1.3, containing the fields that describe the certificate to Section 7.1.3, containing the fields that describe the certificate to
be issued: be issued:
csr (required, string): A CSR encoding the parameters for the identifiers (required, array of object): An array of identifier
certificate being requested [RFC2986]. The CSR is sent in the objects that the client wishes to submit an order for.
base64url-encoded version of the DER format. (Note: Because this
field uses base64url, and does not include headers, it is type (required, string): The type of identifier.
different from PEM.)
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]
notAfter (optional, string): The requested value of the notAfter notAfter (optional, string): The requested value of the notAfter
field in the certificate, in the date format defined in [RFC3339] field in the certificate, in the date format defined in [RFC3339]
POST /acme/new-order HTTP/1.1 POST /acme/new-order 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/1", "kid": "https://example.com/acme/acct/1",
"nonce": "5XJ1L3lEkMG7tR6pA00clA", "nonce": "5XJ1L3lEkMG7tR6pA00clA",
"url": "https://example.com/acme/new-order" "url": "https://example.com/acme/new-order"
}), }),
"payload": base64url({ "payload": base64url({
"csr": "5jNudRx6Ye4HzKEqT5...FS6aKdZeGsysoCo4H9P", "identifiers": [{"type:"dns","value":"example.com"}],
"notBefore": "2016-01-01T00:00:00Z", "notBefore": "2016-01-01T00:00:00Z",
"notAfter": "2016-01-08T00:00:00Z" "notAfter": "2016-01-08T00:00:00Z"
}), }),
"signature": "H6ZXtGjTZyUnPeKn...wEA4TklBdh3e454g" "signature": "H6ZXtGjTZyUnPeKn...wEA4TklBdh3e454g"
} }
The CSR encodes the client's requests with regard to the content of
the certificate to be issued. The CSR MUST indicate the requested
identifiers, either in the commonName portion of the requested
subject name, or in an extensionRequest attribute [RFC2985]
requesting a subjectAltName extension.
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 MUST NOT issue a certificate with contents other than
those requested. If the server requires the request to be modified those requested. If the server requires the request to be modified
in a certain way, it should indicate the required changes using an in a certain way, it should indicate the required changes using an
appropriate error type and description. 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
Location: https://example.com/acme/order/asdf Location: https://example.com/acme/order/asdf
{ {
"status": "pending", "status": "pending",
"expires": "2016-01-01T00:00:00Z", "expires": "2016-01-01T00:00:00Z",
"csr": "jcRf4uXra7FGYW5ZMewvV...rhlnznwy8YbpMGqwidEXfE",
"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": [
{ "type:"dns", "value":"example.com" },
{ "type:"dns", "value":"www.example.com" }
],
"authorizations": [ "authorizations": [
"https://example.com/acme/authz/1234", "https://example.com/acme/authz/1234",
"https://example.com/acme/authz/2345" "https://example.com/acme/authz/2345"
] ],
"finalize": "https://example.com/acme/order/asdf/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 issue the requested certificate. In the time, then the server will be willing to finalize the order upon
order object, any authorization referenced in the "authorizations" request and issue the requested certificate. In the order object,
array whose status is "pending" represents an authorization any authorization referenced in the "authorizations" array whose
transaction that the client must complete before the server will status is "pending" represents an authorization transaction that the
issue the certificate (see Section 7.5). If the client fails to client must complete before the server will issue the certificate
complete the required actions before the "expires" time, then the (see Section 7.5). If the client fails to complete the required
server SHOULD change the status of the order to "invalid" and MAY actions before the "expires" time, then the server SHOULD change the
delete the order resource. status of the order to "invalid" and MAY delete the order resource.
The server MUST begin the issuance process for the requested
certificate and update the order resource with a URL for the
certificate once the client has fulfilled the server's requirements.
If the client has already satisfied the server's requirements at the
time of this request (e.g., by obtaining authorization for all of the
identifiers in the certificate in previous transactions), then the
server MUST proactively issue the requested certificate and provide a
URL for it in the "certificate" field of the order. The server MUST,
however, still list the completed authorizations in the
"authorizations" array.
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 GET request to the order resource to obtain its it should send a POST request to the order resource's finalize URL.
current state. The status of the order will indicate what action the The POST body MUST include a CSR:
client should take:
csr (required, string): A CSR encoding the parameters for the
certificate being requested [RFC2986]. The CSR is sent in the
base64url-encoded version of the DER format. (Note: Because this
field uses base64url, and does not include headers, it is
different from PEM.).
POST /acme/order/asdf/finalize HTTP/1.1
Host: example.com
Content-Type: application/jose+json
{
"protected": base64url({
"alg": "ES256",
"kid": "https://example.com/acme/acct/1",
"nonce": "MSF2j2nawWHPxxkE3ZJtKQ",
"url": "https://example.com/acme/order/asdf/finalize"
}),
"payload": base64url({
"csr": "5jNudRx6Ye4HzKEqT5...FS6aKdZeGsysoCo4H9P",
}),
"signature": "uOrUfIIk5RyQ...nw62Ay1cl6AB"
}
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
set of requested identifiers as the initial new-order request, either
in the commonName portion of the requested subject name, or in an
extensionRequest attribute [RFC2985] requesting a subjectAltName
extension.
A request to finalize an order will result in error if the order
indicated does not have status "pending", if the CSR and order
identifiers differ, or if the account is not authorized for the
identifiers indicated in the CSR.
A valid request to finalize an order will return the order to be
finalized. The client should begin polling the order by sending a
GET request to the order resource to obtain its current state. 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 "processing": The server agrees that the requirements have been o "processing": The server agrees that the requirements have been
fulfilled, and is in the process of generating the certificate. fulfilled, and is in the process of generating the certificate.
Retry after the time given in the "Retry-After" header field of Retry 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. URL to the "certificate" field of the order.
HTTP/1.1 200 Ok
Replay-Nonce: CGf81JWBsq8QyIgPCi9Q9X
Location: https://example.com/acme/order/asdf
{
"status": "valid",
"expires": "2016-01-01T00:00:00Z",
"notBefore": "2016-01-01T00:00:00Z",
"notAfter": "2016-01-08T00:00:00Z",
"identifiers": [
{ "type:"dns", "value":"example.com" },
{ "type:"dns", "value":"www.example.com" }
],
"authorizations": [
"https://example.com/acme/authz/1234",
"https://example.com/acme/authz/2345"
],
"finalize": "https://example.com/acme/order/asdf/finalize",
"certificate": "https://example.com/acme/cert/asdf"
}
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 for an external, non-ACME process for authorizing a client to issue
identifier. In these case, the CA should provision its ACME server certificates for an identifier. In these cases, the CA should
with authorization objects corresponding to these authorizations and provision its ACME server with authorization objects corresponding to
reflect them as already valid in any orders submitted by the client. these authorizations and reflect them as already valid in any orders
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
"new-authz" with a URL for the new authorization resource. "newAuthz" with a URL for the new authorization 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 new-authorization resource specifying the identifier
for which authorization is being requested and how the server should for which authorization is being requested.
behave with respect to existing authorizations for this identifier.
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. 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
skipping to change at page 39, line 22 skipping to change at page 43, line 31
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 to a
key pair (e.g., to request certificates with multiple identifiers), key pair (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). The server may declare multiple entities to manage certificates).
that an authorization is only valid for a specific order by setting
the "scope" field of the authorization to the URL for that order.
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 certificate orders or authorization requests submitted by an account
key holder; their URLs are provided to the client in the responses to key holder; their URLs are provided to the client in the responses to
these requests. The authorization object is implicitly tied to the these requests. The authorization object is implicitly tied to the
account key used to sign the request. account key used to sign the request.
When a client receives an order from the server it downloads the When a client receives an order from the server it downloads the
authorization resources by sending GET requests to the indicated authorization resources by sending GET requests to the indicated
URLs. If the client initiates authorization using a request to the URLs. If the client initiates authorization using a request to the
skipping to change at page 40, line 24 skipping to change at page 44, line 24
"expires": "2018-03-03T14:09:00Z", "expires": "2018-03-03T14:09:00Z",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.org" "value": "example.org"
}, },
"challenges": [ "challenges": [
{ {
"type": "http-01", "type": "http-01",
"url": "https://example.com/authz/1234/0", "url": "https://example.com/acme/authz/1234/0",
"token": "DGyRejmCefe7v4NfDGDKfA" "token": "DGyRejmCefe7v4NfDGDKfA"
}, },
{ {
"type": "tls-sni-02", "type": "tls-sni-02",
"url": "https://example.com/authz/1234/1", "url": "https://example.com/acme/authz/1234/1",
"token": "DGyRejmCefe7v4NfDGDKfA" "token": "DGyRejmCefe7v4NfDGDKfA"
}, },
{ {
"type": "dns-01", "type": "dns-01",
"url": "https://example.com/authz/1234/2", "url": "https://example.com/acme/authz/1234/2",
"token": "DGyRejmCefe7v4NfDGDKfA" "token": "DGyRejmCefe7v4NfDGDKfA"
} }
] ]
} }
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 respond with information to complete the challenges. client needs to respond with information to complete the challenges.
To do this, the client updates the authorization object received from To do this, the client updates the authorization object received from
the server by filling in any required information in the elements of the server by filling in any required information in the elements of
the "challenges" dictionary. the "challenges" dictionary.
The client sends these updates back to the server in the form of a The client sends these updates back to the server in the form of a
JSON object with the response fields required by the challenge type, JSON object with contents as specified by the challenge type, carried
carried in a POST request to the challenge URL (not authorization in a POST request to the challenge URL (not authorization URL) once
URL) once it is ready for the server to attempt validation. it is ready for the server to attempt validation.
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/authz/1234/0 HTTP/1.1 POST /acme/authz/1234/0 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 41, line 26 skipping to change at page 45, line 26
"nonce": "Q_s3MWoqT05TrdkM2MTDcw", "nonce": "Q_s3MWoqT05TrdkM2MTDcw",
"url": "https://example.com/acme/authz/1234/0" "url": "https://example.com/acme/authz/1234/0"
}), }),
"payload": base64url({ "payload": base64url({
"keyAuthorization": "IlirfxKKXA...vb29HhjjLPSggwiE" "keyAuthorization": "IlirfxKKXA...vb29HhjjLPSggwiE"
}), }),
"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 fields 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 The server provides a 200 (OK) response with the updated challenge
object as its body. 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
skipping to change at page 42, line 31 skipping to change at page 46, line 31
"expires": "2018-09-09T14:09:00Z", "expires": "2018-09-09T14:09:00Z",
"identifier": { "identifier": {
"type": "dns", "type": "dns",
"value": "example.org" "value": "example.org"
}, },
"challenges": [ "challenges": [
{ {
"type": "http-01" "type": "http-01"
"url": "https://example.com/authz/1234/0", "url": "https://example.com/acme/authz/1234/0",
"status": "valid", "status": "valid",
"validated": "2014-12-01T12:05:00Z", "validated": "2014-12-01T12:05:00Z",
"token": "IlirfxKKXAsHtmzK29Pj8A", "token": "IlirfxKKXAsHtmzK29Pj8A",
"keyAuthorization": "IlirfxKKXA...vb29HhjjLPSggwiE" "keyAuthorization": "IlirfxKKXA...vb29HhjjLPSggwiE"
} }
] ]
} }
7.5.2. Deactivating an Authorization 7.5.2. Deactivating an Authorization
skipping to change at page 45, line 18 skipping to change at page 49, line 18
--- or --- --- or ---
HTTP/1.1 403 Forbidden HTTP/1.1 403 Forbidden
Replay-Nonce: IXVHDyxIRGcTE0VSblhPzw Replay-Nonce: IXVHDyxIRGcTE0VSblhPzw
Content-Type: application/problem+json Content-Type: application/problem+json
Content-Language: en Content-Language: en
{ {
"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.net"
"instance": "http://example.com/doc/unauthorized"
} }
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.
skipping to change at page 45, line 50 skipping to change at page 49, line 49
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.
This section describes an initial set of challenge types. Each This section describes an initial set of challenge types. The
challenge must describe: definition of a challenge type includes:
1. Content of challenge objects 1. Content of challenge objects
2. Content of response objects 2. Content of response objects
3. How the server uses the challenge and response to verify control 3. How the server uses the challenge and response to verify control
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.
skipping to change at page 46, line 19 skipping to change at page 50, line 16
3. How the server uses the challenge and response to verify control 3. How the server uses the challenge and response to verify control
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 authorization. status (required, string): The status of this challenge. Possible
Possible values are: "pending", "valid", and "invalid". values are: "pending", "valid", and "invalid".
validated (optional, string): The time at which this challenge was validated (optional, string): The time at which the server validated
completed by the server, encoded in the format specified in RFC this challenge, encoded in the format specified in RFC 3339
3339 [RFC3339]. This field is REQUIRED if the "status" field is [RFC3339]. This field is REQUIRED if the "status" field is
"valid". "valid".
errors (optional, array of object): Errors that occurred while the errors (optional, array of object): Errors that occurred while the
server was validating the challenge, if any, structured as problem server was validating the challenge, if any, structured as problem
documents [RFC7807]. The server MUST NOT modify the array except documents [RFC7807]. The server MUST NOT modify the array except
by appending entries onto the end. The server can limit the size by appending entries onto the end. The server can limit the size
of this object by limiting the number of times it will retry a of this object by limiting the number of times it will try to
challenge. validate a challenge.
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 "errors" field to help the client diagnose why the
challenge failed. challenge failed.
Different challenges allow the server to obtain proof of different Different challenges allow the server to obtain proof of different
aspects of control over an identifier. In some challenges, like aspects of control over an identifier. In some challenges, like
HTTP, TLS SNI, and DNS, the client directly proves its ability to do HTTP, TLS SNI, and DNS, the client directly proves its ability to do
certain things related to the identifier. The choice of which certain things related to the identifier. The choice of which
challenges to offer to a client under which circumstances is a matter challenges to offer to a client under which circumstances is a matter
of server policy. of server policy.
The identifier validation challenges described in this section all The identifier validation challenges described in this section all
skipping to change at page 47, line 17 skipping to change at page 51, line 17
Several of the challenges in this document make use of a key Several of the challenges in this document make use of a key
authorization string. A key authorization is a string that expresses authorization string. A key authorization is a string that expresses
a domain holder's authorization for a specified key to satisfy a a domain holder's authorization for a specified key to satisfy a
specified challenge, by concatenating the token for the challenge specified challenge, by concatenating the token for the challenge
with a key fingerprint, separated by a "." character: with a key fingerprint, separated by a "." character:
key-authz = token || '.' || base64url(JWK_Thumbprint(accountKey)) key-authz = token || '.' || base64url(JWK_Thumbprint(accountKey))
The "JWK_Thumbprint" step indicates the computation specified in The "JWK_Thumbprint" step indicates the computation specified in
[RFC7638], using the SHA-256 digest [FIPS180-4]. As noted in JWA [RFC7638], using the SHA-256 digest [FIPS180-4]. As noted in JWA
[RFC7518] any prepended zero octets in the JWK object MUST be [RFC7518] any prepended zero octets in the fields of a JWK object
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. query fails, the server SHOULD retry the query after some time, in
While the server is still trying, the status of the challenge remains order to account for delay in setting up responses such as DNS
"pending"; it is only marked "invalid" once the server has given up. records or HTTP resources. The precise retry schedule is up to the
server, but server operators should keep in mind the operational
scenarios that the schedule is trying to accommodate. Given that
retries are intended to address things like propagation delays in
HTTP or DNS provisioning, there should not usually be any reason to
retry more often than every 5 or 10 seconds. While the server is
still trying, the status of the challenge remains "pending"; it is
only marked "invalid" once the server has given up.
The server MUST provide information about its retry state to the The server MUST provide information about its retry state to the
client via the "errors" field in the challenge and the Retry-After client via the "errors" field in the challenge and the Retry-After
HTTP header field in response to requests to the challenge resource. HTTP header field in response to requests to the challenge resource.
The server MUST add an entry to the "errors" field in the challenge The server MUST add an entry to the "errors" field in the challenge
after each failed validation query. The server SHOULD set the Retry- after each failed validation query. The server SHOULD set the Retry-
After header field to a time after the server's next validation After header field to a time after the server's next validation
query, since the status of the challenge will not change until that query, since the status of the challenge will not change until that
time. time.
skipping to change at page 48, line 11 skipping to change at page 52, line 18
to a challenge in a new POST request (with a new nonce, etc.). This to a challenge in a new POST request (with a new nonce, etc.). This
allows clients to request a retry when the state has changed (e.g., allows clients to request a retry when the state has changed (e.g.,
after firewall rules have been updated). Servers SHOULD retry a after firewall rules have been updated). Servers SHOULD retry a
request immediately on receiving such a POST request. In order to request immediately on receiving such a POST request. In order to
avoid denial-of-service attacks via client-initiated retries, servers avoid denial-of-service attacks via client-initiated retries, servers
SHOULD rate-limit such requests. SHOULD rate-limit such requests.
8.3. HTTP Challenge 8.3. HTTP Challenge
With HTTP validation, the client in an ACME transaction proves its With HTTP validation, the client in an ACME transaction proves its
control over a domain name by proving that for that domain name it control over a domain name by proving that it can provision HTTP
can provision resources to be returned by an HTTP server. The ACME resources on a server accessible under that domain name. The ACME
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,
including padding characters ("="). and MUST NOT include base64 padding characters ("=").
GET /acme/authz/1234/0 HTTP/1.1 GET /acme/authz/1234/0 HTTP/1.1
Host: example.com Host: example.com
HTTP/1.1 200 OK HTTP/1.1 200 OK
{ {
"type": "http-01", "type": "http-01",
"url": "https://example.com/acme/authz/0", "url": "https://example.com/acme/authz/0",
"status": "pending", "status": "pending",
"token": "LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0" "token": "LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0"
skipping to change at page 49, line 11 skipping to change at page 53, line 18
fixed prefix "/.well-known/acme-challenge/", followed by the "token" fixed prefix "/.well-known/acme-challenge/", followed by the "token"
value in the challenge. The value of the resource MUST be the ASCII value in the challenge. The value of the resource MUST be the ASCII
representation of the key authorization. representation of the key authorization.
GET /.well-known/acme-challenge/LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0 GET /.well-known/acme-challenge/LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0
Host: example.org Host: example.org
HTTP/1.1 200 OK HTTP/1.1 200 OK
LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0.9jg46WB3rR_AHD-EBXdN7cBkH1WOu0tA3M9fm21mqTI LoqXcYV8q5ONbJQxbmR7SCTNo3tiAXDfowyjxAjEuX0.9jg46WB3rR_AHD-EBXdN7cBkH1WOu0tA3M9fm21mqTI
The client's response to this challenge indicates its agreement to The client's response to the validation request indicates its
this challenge by sending the server the key authorization covering agreement to this challenge by sending the server the key
the challenge's token and the client's account key. authorization covering the challenge's token and the client's account
key.
keyAuthorization (required, string): The key authorization for this keyAuthorization (required, string): The key authorization for this
challenge. This value MUST match the token from the challenge and challenge. This value MUST match the token from the challenge and
the client's account key. the client's account key.
POST /acme/authz/1234/0 POST /acme/authz/1234/0
Host: example.com Host: example.com
Content-Type: application/jose+json Content-Type: application/jose+json
{ {
skipping to change at page 49, line 47 skipping to change at page 54, line 10
authorization in the response matches the "token" value in the authorization in the response matches the "token" value in the
challenge and the client's account key. If they do not match, then challenge and the client's account key. If they do not match, then
the server MUST return an HTTP error in response to the POST request the server MUST return an HTTP error in response to the POST request
in which the client sent the challenge. in which the client sent the challenge.
Given a challenge/response pair, the server verifies the client's Given a challenge/response pair, the server verifies the client's
control of the domain by verifying that the resource was provisioned control of the domain by verifying that the resource was provisioned
as expected. as expected.
1. Construct a URL by populating the URL template [RFC6570] 1. Construct a URL by populating the URL template [RFC6570]
"http://{domain}/.well-known/acme-challenge/{token}", where: * "http://{domain}/.well-known/acme-challenge/{token}", where:
the domain field is set to the domain name being verified; and *
the token field is set to the token in the challenge. * the domain field is set to the domain name being verified; and
* the token field is set to the token in the challenge.
2. Verify that the resulting URL is well-formed. 2. Verify that the resulting URL is well-formed.
3. Dereference the URL using an HTTP GET request. This request MUST 3. Dereference the URL using an HTTP GET request. This request MUST
be sent to TCP port 80 on the HTTP server. be sent to TCP port 80 on the HTTP server.
4. Verify that the body of the response is well-formed key 4. Verify that the body of the response is well-formed key
authorization. The server SHOULD ignore whitespace characters at authorization. The server SHOULD ignore whitespace characters at
the end of the body. the end of the body.
skipping to change at page 53, line 4 skipping to change at page 57, line 28
GET /acme/authz/1234/2 HTTP/1.1 GET /acme/authz/1234/2 HTTP/1.1
Host: example.com Host: example.com
HTTP/1.1 200 OK HTTP/1.1 200 OK
{ {
"type": "dns-01", "type": "dns-01",
"url": "https://example.com/acme/authz/1234/2", "url": "https://example.com/acme/authz/1234/2",
"status": "pending", "status": "pending",
"token": "evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA" "token": "evaGxfADs6pSRb2LAv9IZf17Dt3juxGJ-PCt92wr-oA"
} }
A client responds to this challenge by constructing a key A client responds to this challenge by constructing a key
authorization from the "token" value provided in the challenge and authorization from the "token" value provided in the challenge and
the client's account key. The client then computes the SHA-256 the client's account key. The client then computes the SHA-256
digest [FIPS180-4] of the key authorization. digest [FIPS180-4] of the key authorization.
The record provisioned to the DNS is the base64url encoding of this The record provisioned to the DNS contains the base64url encoding of
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 "example.org", then the client would provision the following DNS
record: record:
_acme-challenge.example.org. 300 IN TXT "gfj9Xq...Rg85nM" _acme-challenge.example.org. 300 IN TXT "gfj9Xq...Rg85nM"
The response to the DNS challenge provides the computed key The response to the DNS challenge provides the computed key
authorization to acknowledge that the client is ready to fulfill this authorization to acknowledge that the client is ready to fulfill this
skipping to change at page 54, line 16 skipping to change at page 58, line 41
2. Query for TXT records for the validation domain name 2. Query for TXT records for the validation domain name
3. Verify that the contents of one of the TXT records match the 3. Verify that the contents of one of the TXT records match the
digest value digest value
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.
8.6. Out-of-Band Challenge
There may be cases where a server cannot perform automated validation
of an identifier, for example, if validation requires some manual
steps. In such cases, the server may provide an "out of band" (OOB)
challenge to request that the client perform some action outside of
ACME in order to validate possession of the identifier.
The OOB challenge requests that the client have a human user visit a
web page to receive instructions on how to validate possession of the
identifier, by providing a URL for that web page.
type (required, string): The string "oob-01"
href (required, string): The URL to be visited. The scheme of this
URL MUST be "http" or "https". Note that this field is distinct
from the "url" field of the challenge, which identifies the
challenge itself.
GET /acme/authz/1234/3 HTTP/1.1
Host: example.com
HTTP/1.1 200 OK
{
"type": "oob-01",
"url": "https://example.com/acme/authz/1234/3",
"status": "pending",
"href": "https://example.com/validate/evaGxfADs6pSRb2LAv9IZ"
}
A client responds to this challenge by presenting the indicated URL
for a human user to navigate to. If the user chooses to complete
this challenge (by visiting the website and completing its
instructions), the client indicates this by sending a simple
acknowledgement response to the server.
type (required, string): The string "oob-01"
POST /acme/authz/1234/3
Host: example.com
Content-Type: application/jose+json
{
"protected": base64url({
"alg": "ES256",
"kid": "https://example.com/acme/acct/1",
"nonce": "JHb54aT_KTXBWQOzGYkt9A",
"url": "https://example.com/acme/authz/1234/3"
}),
"payload": base64url({
"type": "oob-01"
}),
"signature": "Q1bURgJoEslbD1c5...3pYdSMLio57mQNN4"
}
On receiving a response, the server MUST verify that the value of the
"type" field is "oob-01". Otherwise, the steps the server takes to
validate identifier possession are determined by the server's local
policy.
9. IANA Considerations 9. IANA Considerations
9.1. MIME Type: application/pem-certificate-chain 9.1. MIME Type: application/pem-certificate-chain
The "Media Types" registry should be updated with the following The "Media Types" registry should be updated with the following
additional value: additional value:
MIME media type name: application MIME media type name: application
MIME subtype name: pem-certificate-chain MIME subtype name: pem-certificate-chain
skipping to change at page 56, line 4 skipping to change at page 59, line 16
Encoding considerations: None Encoding considerations: None
Security considerations: Carries a cryptographic certificate and its Security considerations: Carries a cryptographic certificate and its
associated certificate chain associated certificate chain
Interoperability considerations: None Interoperability considerations: None
Published specification: draft-ietf-acme-acme [[ RFC EDITOR: Please Published specification: draft-ietf-acme-acme [[ RFC EDITOR: Please
replace draft-ietf-acme-acme above with the RFC number assigned to replace draft-ietf-acme-acme above with the RFC number assigned to
this ]] this ]]
Applications which use this media type: Any MIME-compliant transport Applications which use this media type: Any MIME-compliant transport
Additional information: Additional information:
File should contain one or more certificates encoded as PEM according File contains one or more certificates encoded with the PEM textual
to RFC 7468 [RFC7468]. In order to provide easy interoperation with encoding, according to RFC 7468 [RFC7468]. In order to provide easy
TLS, the first certificate MUST be an end-entity certificate. Each interoperation with TLS, the first certificate MUST be an end-entity
following certificate SHOULD directly certify one preceding it. certificate. Each following certificate SHOULD directly certify one
Because certificate validation requires that trust anchors be preceding it. Because certificate validation requires that trust
distributed independently, a certificate that specifies a trust anchors be distributed independently, a certificate that specifies a
anchor MAY be omitted from the chain, provided that supported peers trust anchor MAY be omitted from the chain, provided that supported
are known to possess any omitted certificates. peers are known to possess any omitted certificates.
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 "Well-Known URIs" registry should be updated with the following
additional value (using the template from [RFC5785]): additional value (using the template from [RFC5785]):
URI suffix: acme-challenge URI suffix: acme-challenge
Change controller: IETF Change controller: IETF
skipping to change at page 58, line 4 skipping to change at page 61, line 22
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned [[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document, and replace URL-TBD with the URL assigned by IANA to this document, and replace URL-TBD with the URL assigned by IANA
for registries of ACME parameters. ]] for registries of ACME parameters. ]]
9.7. New Registries 9.7. New Registries
This document requests that IANA create the following new registries: This document requests that IANA create the following new 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 Error Types (Section 9.7.3) 3. ACME Error Types (Section 9.7.4)
4. ACME Resource Types (Section 9.7.4) 4. ACME Resource Types (Section 9.7.5)
5. ACME Identifier Types (Section 9.7.5) 5. ACME Directory Metadata Fields (Section 9.7.6)
6. ACME Validation Methods (Section 9.7.6) 6. ACME Identifier Types (Section 9.7.7)
7. 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 This registry lists field names that are defined for use in ACME
account objects. Fields marked as "configurable" may be included in account objects. Fields marked as "configurable" may be included in
a new-account request. a new-account request.
skipping to change at page 59, line 5 skipping to change at page 62, line 13
boolean, array of string boolean, array of string
o Client configurable: Boolean indicating whether the server should o Client configurable: Boolean indicating whether the server should
accept values provided by the client accept 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 7.1.2. Section 7.1.2.
+--------------------------+-------------+--------------+-----------+ +------------------------+---------------+--------------+-----------+
| Field Name | Field Type | Configurable | Reference | | Field Name | Field Type | Configurable | Reference |
+--------------------------+-------------+--------------+-----------+ +------------------------+---------------+--------------+-----------+
| status | string | false | RFC XXXX | | status | string | false | RFC XXXX |
| | | | | | | | | |
| contact | array of | true | RFC XXXX | | contact | array of | true | RFC XXXX |
| | string | | | | | string | | |
| | | | | | | | | |
| external-account-binding | object | true | RFC XXXX | | externalAccountBinding | object | true | RFC XXXX |
| | | | | | | | | |
| terms-of-service-agreed | boolean | true | RFC XXXX | | termsOfServiceAgreed | boolean | true | RFC XXXX |
| | | | | | | | | |
| orders | array of | false | RFC XXXX | | orders | array of | false | RFC XXXX |
| | string | | | | | string | | |
+--------------------------+-------------+--------------+-----------+ +------------------------+---------------+--------------+-----------+
[[ 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 This registry lists field names that are defined for use in ACME
order objects. Fields marked as "configurable" may be included in a order objects. Fields marked as "configurable" may be included in a
new-order request. new-order 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
skipping to change at page 60, line 12 skipping to change at page 63, line 12
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 XXXX |
| | | | | | | | | |
| expires | string | false | RFC XXXX | | expires | string | false | RFC XXXX |
| | | | | | | | | |
| csr | string | true | RFC XXXX | | identifiers | array of object | true | RFC XXXX |
| | | | | | | | | |
| notBefore | string | true | RFC XXXX | | notBefore | string | true | RFC XXXX |
| | | | | | | | | |
| notAfter | string | true | RFC XXXX | | notAfter | string | true | RFC XXXX |
| | | | | | | | | |
| authorizations | array of string | false | RFC XXXX | | authorizations | array of string | false | RFC XXXX |
| | | | | | | | | |
| finalize | string | false | RFC XXXX |
| | | | |
| certificate | string | false | RFC XXXX | | certificate | string | false | RFC XXXX |
+----------------+-----------------+--------------+-----------+ +----------------+-----------------+--------------+-----------+
9.7.3. Error Types [[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.3. Fields in Authorization Objects
This registry lists field names that are defined for use in ACME
authorization objects. Fields marked as "configurable" may be
included in a new-authorization request.
Template:
o Field name: The string to be used as a field name in the JSON
object
o Field type: The type of value to be provided, e.g., string,
boolean, array of string
o Client configurable: Boolean indicating whether the server should
accept values provided by the client
o Reference: Where this field is defined
Initial contents: The fields and descriptions defined in
Section 7.1.4.
+------------+-----------------+--------------+-----------+
| Field Name | Field Type | Configurable | Reference |
+------------+-----------------+--------------+-----------+
| identifier | object | true | RFC XXXX |
| | | | |
| status | string | false | RFC XXXX |
| | | | |
| expires | string | false | RFC XXXX |
| | | | |
| challenges | array of object | false | RFC XXXX |
+------------+-----------------+--------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.4. Error Types
This registry lists values that are used within URN values that are This registry lists values that are used within URN values that are
provided in the "type" field of problem documents in ACME. 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 6.6 above, with the Reference field set to point to this Section 6.6 above, with the Reference field set to point to this
specification. specification.
9.7.4. Resource Types 9.7.5. Resource Types
This registry lists the types of resources that ACME servers may list This registry lists the types of resources that ACME servers may list
in their directory objects. 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
skipping to change at page 61, line 4 skipping to change at page 64, line 49
This registry lists the types of resources that ACME servers may list This registry lists the types of resources that ACME servers may list
in their directory objects. 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 |
+-------------+--------------------+-----------+ +------------+--------------------+-----------+
| new-account | New account | RFC XXXX | | newNonce | New nonce | RFC XXXX |
| | | | | | | |
| new-order | New order | RFC XXXX | | newAccount | New account | RFC XXXX |
| | | | | | | |
| revoke-cert | Revoke certificate | RFC XXXX | | newOrder | New order | RFC XXXX |
| | | | | | | |
| key-change | Key change | RFC XXXX | | newAuthz | New authorization | RFC XXXX |
+-------------+--------------------+-----------+ | | | |
| revokeCert | Revoke certificate | RFC XXXX |
| | | |
| keyChange | Key change | RFC XXXX |
| | | |
| meta | Metadata object | RFC XXXX |
+------------+--------------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned [[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]] to this document ]]
9.7.5. Identifier Types 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
object included in the "meta" field of an ACME directory object.
Template:
o Field name: The string to be used as a field name in the JSON
object
o Field type: The type of value to be provided, e.g., string,
boolean, array of string
o Reference: Where this field is defined
Initial contents: The fields and descriptions defined in
Section 7.1.2.
+-------------------------+-----------------+-----------+
| Field Name | Field Type | Reference |
+-------------------------+-----------------+-----------+
| termsOfService | string | RFC XXXX |
| | | |
| website | string | RFC XXXX |
| | | |
| caaIdentities | array of string | RFC XXXX |
| | | |
| externalAccountRequired | boolean | RFC XXXX |
+-------------------------+-----------------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]]
9.7.7. Identifier Types
This registry lists the types of identifiers that can be present in This registry lists the types of identifiers that can be present in
ACME authorization objects. 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
skipping to change at page 61, line 46 skipping to change at page 66, line 43
+-------+-----------+ +-------+-----------+
| Label | Reference | | Label | Reference |
+-------+-----------+ +-------+-----------+
| dns | RFC XXXX | | dns | RFC XXXX |
+-------+-----------+ +-------+-----------+
[[ RFC EDITOR: Please replace XXXX above with the RFC number assigned [[ RFC EDITOR: Please replace XXXX above with the RFC number assigned
to this document ]] to this document ]]
9.7.6. Validation Methods 9.7.8. Validation Methods
This registry lists identifiers for the ways that CAs can validate This registry lists identifiers for the ways that CAs can validate
control of identifiers. Each method's entry must specify whether it control of identifiers. Each method's entry must specify whether it
corresponds to an ACME challenge type. The "Identifier Type" field corresponds to an ACME challenge type. The "Identifier Type" field
must be contained in the Label column of the ACME Identifier Types must be contained in the Label column of the ACME Identifier Types
registry. registry.
Template: Template:
o Label: The identifier for this validation method o Label: The identifier for this validation method
skipping to change at page 62, line 29 skipping to change at page 67, line 25
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 XXXX |
| | | | | | | | | |
| tls-sni-02 | dns | Y | RFC XXXX | | tls-sni-02 | dns | Y | RFC XXXX |
| | | | | | | | | |
| dns-01 | dns | Y | RFC XXXX | | dns-01 | dns | Y | RFC XXXX |
| | | | |
| oob-01 | dns | Y | RFC XXXX |
+------------+-----------------+------+-----------+ +------------+-----------------+------+-----------+
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 take the same set of actions to fulfill two and server to follow take the same set of actions to fulfill two
different validation mechanisms. different validation mechanisms.
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
skipping to change at page 63, line 26 skipping to change at page 68, line 16
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
improperly used by another account improperly used by another account
In this section, we discuss the threat model that underlies ACME and In this section, we discuss the threat model that underlies ACME and
the ways that ACME achieves these security goals within that threat the ways that ACME achieves these security goals within that threat
model. We also discuss the denial-of-service risks that ACME servers model. We also discuss the denial-of-service risks that ACME servers
face, and a few other miscellaneous considerations. face, and a few other miscellaneous considerations.
10.1. Threat model 10.1. Threat Model
As a service on the Internet, ACME broadly exists within the Internet As a service on the Internet, ACME broadly exists within the Internet
threat model [RFC3552]. In analyzing ACME, it is useful to think of threat model [RFC3552]. In analyzing ACME, it is useful to think of
an ACME server interacting with other Internet hosts along two an ACME server interacting with other Internet hosts along two
"channels": "channels":
o An ACME channel, over which the ACME HTTPS requests are exchanged o An ACME channel, over which the ACME HTTPS requests are exchanged
o A validation channel, over which the ACME server performs o A validation channel, over which the ACME server performs
additional requests to validate a client's control of an additional requests to validate a client's control of an
skipping to change at page 68, line 41 skipping to change at page 73, line 27
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 Certificate
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. If a CA wishes to have stronger evidence not involving a human user.
of user consent, it may present an out-of-band requirement or
challenge to require human involvement.
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. For example:
11.1. DNS security 11.1. DNS security
As noted above, DNS forgery attacks against the ACME server can As noted above, DNS forgery attacks against the ACME server can
skipping to change at page 71, line 39 skipping to change at page 76, line 22
13.1. Normative References 13.1. Normative References
[FIPS180-4] [FIPS180-4]
Department of Commerce, National., "NIST FIPS 180-4, Department of Commerce, National., "NIST FIPS 180-4,
Secure Hash Standard", March 2012, Secure Hash Standard", March 2012,
<http://csrc.nist.gov/publications/fips/fips180-4/ <http://csrc.nist.gov/publications/fips/fips180-4/
fips-180-4.pdf>. fips-180-4.pdf>.
[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, <https://www.rfc- DOI 10.17487/RFC2119, March 1997,
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>.
[RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818,
DOI 10.17487/RFC2818, May 2000, <https://www.rfc- DOI 10.17487/RFC2818, May 2000,
editor.org/info/rfc2818>. <https://www.rfc-editor.org/info/rfc2818>.
[RFC2985] Nystrom, M. and B. Kaliski, "PKCS #9: Selected Object [RFC2985] Nystrom, M. and B. Kaliski, "PKCS #9: Selected Object
Classes and Attribute Types Version 2.0", RFC 2985, Classes and Attribute Types Version 2.0", RFC 2985,
DOI 10.17487/RFC2985, November 2000, <https://www.rfc- DOI 10.17487/RFC2985, November 2000,
editor.org/info/rfc2985>. <https://www.rfc-editor.org/info/rfc2985>.
[RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification [RFC2986] Nystrom, M. and B. Kaliski, "PKCS #10: Certification
Request Syntax Specification Version 1.7", RFC 2986, Request Syntax Specification Version 1.7", RFC 2986,
DOI 10.17487/RFC2986, November 2000, <https://www.rfc- DOI 10.17487/RFC2986, November 2000,
editor.org/info/rfc2986>. <https://www.rfc-editor.org/info/rfc2986>.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002, Timestamps", RFC 3339, DOI 10.17487/RFC3339, July 2002,
<https://www.rfc-editor.org/info/rfc3339>. <https://www.rfc-editor.org/info/rfc3339>.
[RFC3492] Costello, A., "Punycode: A Bootstring encoding of Unicode [RFC3492] Costello, A., "Punycode: A Bootstring encoding of Unicode
for Internationalized Domain Names in Applications for Internationalized Domain Names in Applications
(IDNA)", RFC 3492, DOI 10.17487/RFC3492, March 2003, (IDNA)", RFC 3492, DOI 10.17487/RFC3492, March 2003,
<https://www.rfc-editor.org/info/rfc3492>. <https://www.rfc-editor.org/info/rfc3492>.
skipping to change at page 72, line 39 skipping to change at page 77, line 20
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005, RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>. <https://www.rfc-editor.org/info/rfc3986>.
[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>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, (TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008, <https://www.rfc- DOI 10.17487/RFC5246, August 2008,
editor.org/info/rfc5246>. <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>.
[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, [RFC5988] Nottingham, M., "Web Linking", RFC 5988,
DOI 10.17487/RFC5988, October 2010, <https://www.rfc- DOI 10.17487/RFC5988, October 2010,
editor.org/info/rfc5988>. <https://www.rfc-editor.org/info/rfc5988>.
[RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS) [RFC6066] Eastlake 3rd, D., "Transport Layer Security (TLS)
Extensions: Extension Definitions", RFC 6066, Extensions: Extension Definitions", RFC 6066,
DOI 10.17487/RFC6066, January 2011, <https://www.rfc- DOI 10.17487/RFC6066, January 2011,
editor.org/info/rfc6066>. <https://www.rfc-editor.org/info/rfc6066>.
[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, <https://www.rfc- DOI 10.17487/RFC6570, March 2012,
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, <https://www.rfc- DOI 10.17487/RFC6844, January 2013,
editor.org/info/rfc6844>. <https://www.rfc-editor.org/info/rfc6844>.
[RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data [RFC7159] Bray, T., Ed., "The JavaScript Object Notation (JSON) Data
Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March Interchange Format", RFC 7159, DOI 10.17487/RFC7159, March
2014, <https://www.rfc-editor.org/info/rfc7159>. 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, <https://www.rfc- DOI 10.17487/RFC7231, June 2014,
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
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>. 2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518, [RFC7518] Jones, M., "JSON Web Algorithms (JWA)", RFC 7518,
DOI 10.17487/RFC7518, May 2015, <https://www.rfc- DOI 10.17487/RFC7518, May 2015,
editor.org/info/rfc7518>. <https://www.rfc-editor.org/info/rfc7518>.
[RFC7638] Jones, M. and N. Sakimura, "JSON Web Key (JWK) [RFC7638] Jones, M. and N. Sakimura, "JSON Web Key (JWK)
Thumbprint", RFC 7638, DOI 10.17487/RFC7638, September Thumbprint", RFC 7638, DOI 10.17487/RFC7638, September
2015, <https://www.rfc-editor.org/info/rfc7638>. 2015, <https://www.rfc-editor.org/info/rfc7638>.
[RFC7807] Nottingham, M. and E. Wilde, "Problem Details for HTTP [RFC7807] Nottingham, M. and E. Wilde, "Problem Details for HTTP
APIs", RFC 7807, DOI 10.17487/RFC7807, March 2016, APIs", RFC 7807, DOI 10.17487/RFC7807, March 2016,
<https://www.rfc-editor.org/info/rfc7807>. <https://www.rfc-editor.org/info/rfc7807>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
skipping to change at page 74, line 28 skipping to change at page 79, line 12
ACME Method Binding", draft-ietf-acme-caa-03 (work in ACME Method Binding", draft-ietf-acme-caa-03 (work in
progress), August 2017. progress), August 2017.
[I-D.ietf-acme-ip] [I-D.ietf-acme-ip]
Shoemaker, R., "ACME IP Identifier Validation Extension", Shoemaker, R., "ACME IP Identifier Validation Extension",
draft-ietf-acme-ip-01 (work in progress), September 2017. draft-ietf-acme-ip-01 (work in progress), September 2017.
[I-D.ietf-acme-telephone] [I-D.ietf-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", draft-ietf-acme-
telephone-00 (work in progress), July 2017. telephone-01 (work in progress), October 2017.
[I-D.vixie-dnsext-dns0x20] [I-D.vixie-dnsext-dns0x20]
Vixie, P. and D. Dagon, "Use of Bit 0x20 in DNS Labels to Vixie, P. and D. Dagon, "Use of Bit 0x20 in DNS Labels to
Improve Transaction Identity", draft-vixie-dnsext- Improve Transaction Identity", draft-vixie-dnsext-
dns0x20-00 (work in progress), March 2008. dns0x20-00 (work in progress), 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, <https://www.rfc- DOI 10.17487/RFC3552, July 2003,
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, <https://www.rfc- DOI 10.17487/RFC5785, April 2010,
editor.org/info/rfc5785>. <https://www.rfc-editor.org/info/rfc5785>.
[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.CR-cors-20130129] [W3C.CR-cors-20130129]
Kesteren, A., "Cross-Origin Resource Sharing", World Wide Kesteren, A., "Cross-Origin Resource Sharing", World Wide
Web Consortium CR CR-cors-20130129, January 2013, Web Consortium CR CR-cors-20130129, January 2013,
<http://www.w3.org/TR/2013/CR-cors-20130129>. <http://www.w3.org/TR/2013/CR-cors-20130129>.
13.3. URIs
[1] https://github.com/ietf-wg-acme/acme
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
Email: jsha@eff.org Email: jsha@eff.org
Daniel McCarney
Let's Encrypt
Email: cpu@letsencrypt.org
James Kasten James Kasten
University of Michigan University of Michigan
Email: jdkasten@umich.edu Email: jdkasten@umich.edu
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