 1/draftietfjosejsonwebalgorithms02.txt 20120706 19:14:10.961426162 +0200
+++ 2/draftietfjosejsonwebalgorithms03.txt 20120706 19:14:11.025478394 +0200
@@ 1,628 +1,837 @@
JOSE Working Group M. Jones
InternetDraft Microsoft
Intended status: Standards Track May 12, 2012
Expires: November 13, 2012
+Intended status: Standards Track July 6, 2012
+Expires: January 7, 2013
JSON Web Algorithms (JWA)
 draftietfjosejsonwebalgorithms02
+ draftietfjosejsonwebalgorithms03
Abstract
The JSON Web Algorithms (JWA) specification enumerates cryptographic
algorithms and identifiers to be used with the JSON Web Signature
 (JWS) and JSON Web Encryption (JWE) specifications.

Requirements Language

 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
 document are to be interpreted as described in RFC 2119 [RFC2119].
+ (JWS), JSON Web Encryption (JWE), and JSON Web Key (JWK)
+ specifications.
Status of this Memo
This InternetDraft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
InternetDrafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as InternetDrafts. The list of current Internet
Drafts is at http://datatracker.ietf.org/drafts/current/.
InternetDrafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use InternetDrafts as reference
material or to cite them other than as "work in progress."
 This InternetDraft will expire on November 13, 2012.
+ This InternetDraft will expire on January 7, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/licenseinfo) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
+ 1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
 3. Cryptographic Algorithms for JWS . . . . . . . . . . . . . . . 4
 3.1. "alg" (Algorithm) Header Parameter Values for JWS . . . . 4
 3.2. MAC with HMAC SHA256, HMAC SHA384, or HMAC SHA512 . . . 5
+ 2.1. Terms Incorporated from the JWS Specification . . . . . . 4
+ 2.2. Terms Incorporated from the JWE Specification . . . . . . 5
+ 2.3. Terms Incorporated from the JWK Specification . . . . . . 6
+ 2.4. Defined Terms . . . . . . . . . . . . . . . . . . . . . . 7
+ 3. Cryptographic Algorithms for JWS . . . . . . . . . . . . . . . 7
+ 3.1. "alg" (Algorithm) Header Parameter Values for JWS . . . . 7
+ 3.2. MAC with HMAC SHA256, HMAC SHA384, or HMAC SHA512 . . . 8
3.3. Digital Signature with RSA SHA256, RSA SHA384, or
 RSA SHA512 . . . . . . . . . . . . . . . . . . . . . . . 6
+ RSA SHA512 . . . . . . . . . . . . . . . . . . . . . . . 9
3.4. Digital Signature with ECDSA P256 SHA256, ECDSA
 P384 SHA384, or ECDSA P521 SHA512 . . . . . . . . . . 7
 3.5. Creating a Plaintext JWS . . . . . . . . . . . . . . . . . 9
+ P384 SHA384, or ECDSA P521 SHA512 . . . . . . . . . . 10
+ 3.5. Using the Algorithm "none" . . . . . . . . . . . . . . . . 11
3.6. Additional Digital Signature/MAC Algorithms and
 Parameters . . . . . . . . . . . . . . . . . . . . . . . . 9
 4. Cryptographic Algorithms for JWE . . . . . . . . . . . . . . . 9
 4.1. "alg" (Algorithm) Header Parameter Values for JWE . . . . 9
+ Parameters . . . . . . . . . . . . . . . . . . . . . . . . 12
+ 4. Cryptographic Algorithms for JWE . . . . . . . . . . . . . . . 12
+ 4.1. "alg" (Algorithm) Header Parameter Values for JWE . . . . 12
4.2. "enc" (Encryption Method) Header Parameter Values for
 JWE . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
+ JWE . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
4.3. "int" (Integrity Algorithm) Header Parameter Values
 for JWE . . . . . . . . . . . . . . . . . . . . . . . . . 11
 4.4. Key Encryption with RSA using RSAPKCS11.5 Padding . . . 11
 4.5. Key Encryption with RSA using Optimal Asymmetric
 Encryption Padding (OAEP) . . . . . . . . . . . . . . . . 11
 4.6. Key Agreement with Elliptic Curve DiffieHellman
 Ephemeral Static (ECDHES) . . . . . . . . . . . . . . . . 12
 4.7. Key Encryption with AES Key Wrap . . . . . . . . . . . . . 12
 4.8. Plaintext Encryption with AES Cipher Block Chaining
 (CBC) Mode . . . . . . . . . . . . . . . . . . . . . . . . 12
 4.9. Plaintext Encryption with AES Galois/Counter Mode (GCM) . 12
 4.10. Integrity Calculation with HMAC SHA256, HMAC SHA384,
 or HMAC SHA512 . . . . . . . . . . . . . . . . . . . . . 13
 4.11. Additional Encryption Algorithms and Parameters . . . . . 13
 5. Cryptographic Algorithms for JWK . . . . . . . . . . . . . . . 13
 5.1. "alg" (Algorithm Family) Parameter Values for JWK . . . . 14
 5.2. JWK Parameters for Elliptic Curve Keys . . . . . . . . . . 14
 5.2.1. "crv" (Curve) Parameter . . . . . . . . . . . . . . . 14
 5.2.2. "x" (X Coordinate) Parameter . . . . . . . . . . . . . 14
 5.2.3. "y" (Y Coordinate) Parameter . . . . . . . . . . . . . 14
 5.3. JWK Parameters for RSA Keys . . . . . . . . . . . . . . . 14
 5.3.1. "mod" (Modulus) Parameter . . . . . . . . . . . . . . 15
 5.3.2. "exp" (Exponent) Parameter . . . . . . . . . . . . . . 15
 5.4. Additional Key Algorithm Families and Parameters . . . . . 15
+ for JWE . . . . . . . . . . . . . . . . . . . . . . . . . 14
+ 4.4. "kdf" (Key Derivation Function) Header Parameter
+ Values for JWE . . . . . . . . . . . . . . . . . . . . . . 14
+ 4.5. Key Encryption with RSAESPKCS1V1_5 . . . . . . . . . . . 15
+ 4.6. Key Encryption with RSAES OAEP . . . . . . . . . . . . . . 15
+ 4.7. Key Agreement with Elliptic Curve DiffieHellman
+ Ephemeral Static (ECDHES) . . . . . . . . . . . . . . . . 15
+ 4.8. Key Encryption with AES Key Wrap . . . . . . . . . . . . . 15
+ 4.9. Plaintext Encryption with AES CBC Mode . . . . . . . . . . 15
+ 4.10. Plaintext Encryption with AES GCM . . . . . . . . . . . . 16
+ 4.11. Integrity Calculation with HMAC SHA256, HMAC SHA384,
+ or HMAC SHA512 . . . . . . . . . . . . . . . . . . . . . 16
+ 4.12. Key Derivation with Concat KDF and SHA256, SHA384,
+ or SHA512 . . . . . . . . . . . . . . . . . . . . . . . . 16
+ 4.13. Additional Encryption Algorithms and Parameters . . . . . 17
+ 5. Cryptographic Algorithms for JWK . . . . . . . . . . . . . . . 18
+ 5.1. "alg" (Algorithm Family) Parameter Values for JWK . . . . 18
+ 5.2. JWK Parameters for Elliptic Curve Keys . . . . . . . . . . 18
+ 5.2.1. "crv" (Curve) Parameter . . . . . . . . . . . . . . . 18
+ 5.2.2. "x" (X Coordinate) Parameter . . . . . . . . . . . . . 19
+ 5.2.3. "y" (Y Coordinate) Parameter . . . . . . . . . . . . . 19
+ 5.3. JWK Parameters for RSA Keys . . . . . . . . . . . . . . . 19
+ 5.3.1. "mod" (Modulus) Parameter . . . . . . . . . . . . . . 19
+ 5.3.2. "exp" (Exponent) Parameter . . . . . . . . . . . . . . 19
 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
 6.1. JSON Web Signature and Encryption Header Parameters
 Registry . . . . . . . . . . . . . . . . . . . . . . . . . 15
 6.2. JSON Web Signature and Encryption Algorithms Registry . . 15
 6.3. JSON Web Signature and Encryption "typ" Values Registry . 16
 6.4. JSON Web Key Parameters Registry . . . . . . . . . . . . . 16
 6.5. JSON Web Key Algorithm Families Registry . . . . . . . . . 16
 7. Security Considerations . . . . . . . . . . . . . . . . . . . 16
 8. Open Issues and Things To Be Done (TBD) . . . . . . . . . . . 17
 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 17
 9.1. Normative References . . . . . . . . . . . . . . . . . . . 17
 9.2. Informative References . . . . . . . . . . . . . . . . . . 18
+ 5.4. Additional Key Algorithm Families and Parameters . . . . . 19
+ 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
+ 6.1. JSON Web Signature and Encryption Algorithms Registry . . 20
+ 6.1.1. Registration Template . . . . . . . . . . . . . . . . 21
+ 6.1.2. Initial Registry Contents . . . . . . . . . . . . . . 21
+ 6.2. JSON Web Key Algorithm Families Registry . . . . . . . . . 26
+ 6.2.1. Registration Template . . . . . . . . . . . . . . . . 26
+ 6.2.2. Initial Registry Contents . . . . . . . . . . . . . . 27
+ 6.3. JSON Web Key Parameters Registration . . . . . . . . . . . 27
+ 6.3.1. Registry Contents . . . . . . . . . . . . . . . . . . 27
+ 7. Security Considerations . . . . . . . . . . . . . . . . . . . 28
+ 8. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . 29
+ 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 29
+ 9.1. Normative References . . . . . . . . . . . . . . . . . . . 29
+ 9.2. Informative References . . . . . . . . . . . . . . . . . . 31
Appendix A. Digital Signature/MAC Algorithm Identifier
 CrossReference . . . . . . . . . . . . . . . . . . . 19
 Appendix B. Encryption Algorithm Identifier CrossReference . . . 21
 Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 25
 Appendix D. Document History . . . . . . . . . . . . . . . . . . 25
 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 26
+ CrossReference . . . . . . . . . . . . . . . . . . . 32
+ Appendix B. Encryption Algorithm Identifier CrossReference . . . 34
+ Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 36
+ Appendix D. Document History . . . . . . . . . . . . . . . . . . 36
+ Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 39
1. Introduction
The JSON Web Algorithms (JWA) specification enumerates cryptographic
algorithms and identifiers to be used with the JSON Web Signature
 (JWS) [JWS] and JSON Web Encryption (JWE) [JWE] specifications.
+ (JWS) [JWS], JSON Web Encryption (JWE) [JWE], and JSON Web Key (JWK)
+ [JWK] specifications. This specification also describes the
+ semantics and operations that are specific to these algorithms and
+ algorithm families.
+
Enumerating the algorithms and identifiers for them in this
 specification, rather than in the JWS and JWE specifications, is
 intended to allow them to remain unchanged in the face of changes in
 the set of required, recommended, optional, and deprecated algorithms
 over time. This specification also describes the semantics and
 operations that are specific to these algorithms and algorithm
 families.
+ specification, rather than in the JWS, JWE, and JWK specifications,
+ is intended to allow them to remain unchanged in the face of changes
+ in the set of required, recommended, optional, and deprecated
+ algorithms over time.
+
+1.1. Notational Conventions
+
+ The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
+ "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
+ document are to be interpreted as described in Key words for use in
+ RFCs to Indicate Requirement Levels [RFC2119].
2. Terminology
 This specification uses the terminology defined by the JSON Web
 Signature (JWS) [JWS] and JSON Web Encryption (JWE) [JWE]
 specifications.
+2.1. Terms Incorporated from the JWS Specification
+
+ These terms defined by the JSON Web Signature (JWS) [JWS]
+ specification are incorporated into this specification:
+
+ JSON Web Signature (JWS) A data structure cryptographically securing
+ a JWS Header and a JWS Payload with a JWS Signature value.
+
+ JWS Header A string representing a JavaScript Object Notation (JSON)
+ [RFC4627] object that describes the digital signature or MAC
+ operation applied to create the JWS Signature value.
+
+ JWS Payload The bytes to be secured  a.k.a., the message. The
+ payload can contain an arbitrary sequence of bytes.
+
+ JWS Signature A byte array containing the cryptographic material
+ that secures the contents of the JWS Header and the JWS Payload.
+
+ Encoded JWS Header Base64url encoding of the bytes of the UTF8
+ [RFC3629] representation of the JWS Header.
+
+ Encoded JWS Payload Base64url encoding of the JWS Payload.
+
+ Encoded JWS Signature Base64url encoding of the JWS Signature.
+
+ JWS Secured Input The concatenation of the Encoded JWS Header, a
+ period ('.') character, and the Encoded JWS Payload.
+
+ Base64url Encoding For the purposes of this specification, this term
+ always refers to the URL and filenamesafe Base64 encoding
+ described in RFC 4648 [RFC4648], Section 5, with the (non URL
+ safe) '=' padding characters omitted, as permitted by Section 3.2.
+ (See Appendix C of [JWS] for notes on implementing base64url
+ encoding without padding.)
+
+ Collision Resistant Namespace A namespace that allows names to be
+ allocated in a manner such that they are highly unlikely to
+ collide with other names. For instance, collision resistance can
+ be achieved through administrative delegation of portions of the
+ namespace or through use of collisionresistant name allocation
+ functions. Examples of Collision Resistant Namespaces include:
+ Domain Names, Object Identifiers (OIDs) as defined in the ITUT
+ X.660 and X.670 Recommendation series, and Universally Unique
+ IDentifiers (UUIDs) [RFC4122]. When using an administratively
+ delegated namespace, the definer of a name needs to take
+ reasonable precautions to ensure they are in control of the
+ portion of the namespace they use to define the name.
+
+2.2. Terms Incorporated from the JWE Specification
+
+ These terms defined by the JSON Web Encryption (JWE) [JWE]
+ specification are incorporated into this specification:
+
+ JSON Web Encryption (JWE) A data structure representing an encrypted
+ version of a Plaintext. The structure consists of four parts: the
+ JWE Header, the JWE Encrypted Key, the JWE Ciphertext, and the JWE
+ Integrity Value.
+
+ Plaintext The bytes to be encrypted  a.k.a., the message. The
+ plaintext can contain an arbitrary sequence of bytes.
+
+ Ciphertext The encrypted version of the Plaintext.
+
+ Content Encryption Key (CEK) A symmetric key used to encrypt the
+ Plaintext for the recipient to produce the Ciphertext.
+
+ Content Integrity Key (CIK) A key used with a MAC function to ensure
+ the integrity of the Ciphertext and the parameters used to create
+ it.
+
+ Content Master Key (CMK) A key from which the CEK and CIK are
+ derived. When key wrapping or key encryption are employed, the
+ CMK is randomly generated and encrypted to the recipient as the
+ JWE Encrypted Key. When key agreement is employed, the CMK is the
+ result of the key agreement algorithm.
+
+ JWE Header A string representing a JSON object that describes the
+ encryption operations applied to create the JWE Encrypted Key, the
+ JWE Ciphertext, and the JWE Integrity Value.
+
+ JWE Encrypted Key When key wrapping or key encryption are employed,
+ the Content Master Key (CMK) is encrypted with the intended
+ recipient's key and the resulting encrypted content is recorded as
+ a byte array, which is referred to as the JWE Encrypted Key.
+ Otherwise, when key agreement is employed, the JWE Encrypted Key
+ is the empty byte array.
+
+ JWE Ciphertext A byte array containing the Ciphertext.
+
+ JWE Integrity Value A byte array containing a MAC value that ensures
+ the integrity of the Ciphertext and the parameters used to create
+ it.
+
+ Encoded JWE Header Base64url encoding of the bytes of the UTF8
+ [RFC3629] representation of the JWE Header.
+
+ Encoded JWE Encrypted Key Base64url encoding of the JWE Encrypted
+ Key.
+
+ Encoded JWE Ciphertext Base64url encoding of the JWE Ciphertext.
+
+ Encoded JWE Integrity Value Base64url encoding of the JWE Integrity
+ Value.
+
+ AEAD Algorithm An Authenticated Encryption with Associated Data
+ (AEAD) [RFC5116] encryption algorithm is one that provides an
+ integrated content integrity check. AES Galois/Counter Mode (GCM)
+ is one such algorithm.
+
+2.3. Terms Incorporated from the JWK Specification
+
+ These terms defined by the JSON Web Key (JWK) [JWK] specification are
+ incorporated into this specification:
+
+ JSON Web Key (JWK) A JSON data structure that represents a public
+ key.
+
+ JSON Web Key Set (JWK Set) A JSON object that contains an array of
+ JWKs as a member.
+
+2.4. Defined Terms
+
+ These terms are defined for use by this specification:
+
+ Header Parameter Name The name of a member of the JSON object
+ representing a JWS Header or JWE Header.
+
+ Header Parameter Value The value of a member of the JSON object
+ representing a JWS Header or JWE Header.
3. Cryptographic Algorithms for JWS
 JWS uses cryptographic algorithms to digitally sign or MAC the
 contents of the JWS Header and the JWS Payload. The use of the
 following algorithms for producing JWSs is defined in this section.
+ JWS uses cryptographic algorithms to digitally sign or create a
+ Message Authentication Codes (MAC) of the contents of the JWS Header
+ and the JWS Payload. The use of the following algorithms for
+ producing JWSs is defined in this section.
3.1. "alg" (Algorithm) Header Parameter Values for JWS
The table below is the set of "alg" (algorithm) header parameter
values defined by this specification for use with JWS, each of which
is explained in more detail in the following sections:
 +++
  alg Parameter  Digital Signature or MAC Algorithm 
  Value  
 +++
  HS256  HMAC using SHA256 hash algorithm 
  HS384  HMAC using SHA384 hash algorithm 
  HS512  HMAC using SHA512 hash algorithm 
  RS256  RSA using SHA256 hash algorithm 
  RS384  RSA using SHA384 hash algorithm 
  RS512  RSA using SHA512 hash algorithm 
  ES256  ECDSA using P256 curve and SHA256 hash 
   algorithm 
  ES384  ECDSA using P384 curve and SHA384 hash 
   algorithm 
  ES512  ECDSA using P521 curve and SHA512 hash 
   algorithm 
  none  No digital signature or MAC value included 
 +++
+ ++++
+  alg  Digital Signature or MAC  Implementation 
+  Parameter  Algorithm  Requirements 
+  Value   
+ ++++
+  HS256  HMAC using SHA256 hash  REQUIRED 
+   algorithm  
+  HS384  HMAC using SHA384 hash  OPTIONAL 
+   algorithm  
+  HS512  HMAC using SHA512 hash  OPTIONAL 
+   algorithm  
+  RS256  RSASSA using SHA256 hash  RECOMMENDED 
+   algorithm  
+  RS384  RSASSA using SHA384 hash  OPTIONAL 
+   algorithm  
+  RS512  RSASSA using SHA512 hash  OPTIONAL 
+   algorithm  
+  ES256  ECDSA using P256 curve and  RECOMMENDED+ 
+   SHA256 hash algorithm  
+  ES384  ECDSA using P384 curve and  OPTIONAL 
+   SHA384 hash algorithm  
+  ES512  ECDSA using P521 curve and  OPTIONAL 
+   SHA512 hash algorithm  
+  none  No digital signature or MAC  REQUIRED 
+   value included  
+ ++++
+
+ All the names are short because a core goal of JWS is for the
+ representations to be compact. However, there is no a priori length
+ restriction on "alg" values.
+
+ The use of "+" in the Implementation Requirements indicates that the
+ requirement strength is likely to be increased in a future version of
+ the specification.
See Appendix A for a table crossreferencing the digital signature
and MAC "alg" (algorithm) values used in this specification with the
equivalent identifiers used by other standards and software packages.
 Of these algorithms, only HMAC SHA256 and "none" MUST be implemented
 by conforming JWS implementations. It is RECOMMENDED that
 implementations also support the RSA SHA256 and ECDSA P256 SHA256
 algorithms. Support for other algorithms and key sizes is OPTIONAL.

3.2. MAC with HMAC SHA256, HMAC SHA384, or HMAC SHA512
Hashbased Message Authentication Codes (HMACs) enable one to use a
secret plus a cryptographic hash function to generate a Message
Authentication Code (MAC). This can be used to demonstrate that the
MAC matches the hashed content, in this case the JWS Secured Input,
which therefore demonstrates that whoever generated the MAC was in
possession of the secret. The means of exchanging the shared key is
outside the scope of this specification.
The algorithm for implementing and validating HMACs is provided in
RFC 2104 [RFC2104]. This section defines the use of the HMAC SHA
 256, HMAC SHA384, and HMAC SHA512 cryptographic hash functions as
 defined in FIPS 1803 [FIPS.1803]. The "alg" (algorithm) header
 parameter values "HS256", "HS384", and "HS512" are used in the JWS
 Header to indicate that the Encoded JWS Signature contains a
 base64url encoded HMAC value using the respective hash function.
+ 256, HMAC SHA384, and HMAC SHA512 functions [SHS]. The "alg"
+ (algorithm) header parameter values "HS256", "HS384", and "HS512" are
+ used in the JWS Header to indicate that the Encoded JWS Signature
+ contains a base64url encoded HMAC value using the respective hash
+ function.
A key of the same size as the hash output (for instance, 256 bits for
"HS256") or larger MUST be used with this algorithm.
 The HMAC SHA256 MAC is generated as follows:

 1. Apply the HMAC SHA256 algorithm to the bytes of the UTF8
 representation of the JWS Secured Input (which is the same as the
 ASCII representation) using the shared key to produce an HMAC
 value.

 2. Base64url encode the resulting HMAC value.

 The output is the Encoded JWS Signature for that JWS.

 The HMAC SHA256 MAC for a JWS is validated as follows:

 1. Apply the HMAC SHA256 algorithm to the bytes of the UTF8
 representation of the JWS Secured Input (which is the same as the
 ASCII representation) of the JWS using the shared key.

 2. Base64url encode the resulting HMAC value.

 3. If the Encoded JWS Signature and the base64url encoded HMAC value
 exactly match, then one has confirmation that the shared key was
 used to generate the HMAC on the JWS and that the contents of the
 JWS have not be tampered with.

 4. If the validation fails, the JWS MUST be rejected.
+ The HMAC SHA256 MAC is generated per RFC 2104, using SHA256 as the
+ hash algorithm "H", using the bytes of the ASCII [USASCII]
+ representation of the JWS Secured Input as the "text" value, and
+ using the shared key. The HMAC output value is the JWS Signature.
+ The JWS signature is base64url encoded to produce the Encoded JWS
+ Signature.
 Alternatively, the Encoded JWS Signature MAY be base64url decoded to
 produce the JWS Signature and this value can be compared with the
 computed HMAC value, as this comparison produces the same result as
 comparing the encoded values.
+ The HMAC SHA256 MAC for a JWS is validated by computing an HMAC
+ value per RFC 2104, using SHA256 as the hash algorithm "H", using
+ the bytes of the ASCII representation of the received JWS Secured
+ input as the "text" value, and using the shared key. This computed
+ HMAC value is then compared to the result of base64url decoding the
+ received Encoded JWS signature. Alternatively, the computed HMAC
+ value can be base64url encoded and compared to the received Encoded
+ JWS Signature, as this comparison produces the same result as
+ comparing the unencoded values. In either case, if the values match,
+ the HMAC has been validated. If the validation fails, the JWS MUST
+ be rejected.
Securing content with the HMAC SHA384 and HMAC SHA512 algorithms is
 performed identically to the procedure for HMAC SHA256  just with
 correspondingly larger minimum key sizes and result values.
+ performed identically to the procedure for HMAC SHA256  just using
+ the corresponding hash algorithm with correspondingly larger minimum
+ key sizes and result values: 384 bits each for HMAC SHA384 and 512
+ bits each for HMAC SHA512.
3.3. Digital Signature with RSA SHA256, RSA SHA384, or RSA SHA512
 This section defines the use of the RSASSAPKCS1v1_5 digital
 signature algorithm as defined in RFC 3447 [RFC3447], Section 8.2
 (commonly known as PKCS#1), using SHA256, SHA384, or SHA512 as the
 hash function. The RSASSAPKCS1v1_5 algorithm is described in FIPS
 1863 [FIPS.1863], Section 5.5, and the SHA256, SHA384, and SHA
 512 cryptographic hash functions are defined in FIPS 1803
 [FIPS.1803]. The "alg" (algorithm) header parameter values "RS256",
 "RS384", and "RS512" are used in the JWS Header to indicate that the
 Encoded JWS Signature contains a base64url encoded RSA digital
 signature using the respective hash function.
+ This section defines the use of the RSASSAPKCS1V1_5 digital
+ signature algorithm as defined in Section 8.2 of RFC 3447 [RFC3447],
+ (commonly known as PKCS #1), using SHA256, SHA384, or SHA512 [SHS]
+ as the hash functions. The "alg" (algorithm) header parameter values
+ "RS256", "RS384", and "RS512" are used in the JWS Header to indicate
+ that the Encoded JWS Signature contains a base64url encoded RSA
+ digital signature using the respective hash function.
A key of size 2048 bits or larger MUST be used with these algorithms.
 Note that while Section 8 of RFC 3447 [RFC3447] explicitly calls for
 people not to adopt RSASSAPKCS1 for new applications and instead
 requests that people transition to RSASSAPSS, for interoperability
 reasons, this specification does use RSASSAPKCS1 because it commonly
 implemented.

The RSA SHA256 digital signature is generated as follows:
 1. Generate a digital signature of the bytes of the UTF8
 representation of the JWS Secured Input (which is the same as the
 ASCII representation) using RSASSAPKCS1V1_5SIGN and the SHA
 256 hash function with the desired private key. The output will
 be a byte array.
+ 1. Generate a digital signature of the bytes of the ASCII
+ representation of the JWS Secured Input using RSASSAPKCS1V1_5
+ SIGN and the SHA256 hash function with the desired private key.
+ The output will be a byte array.
2. Base64url encode the resulting byte array.
The output is the Encoded JWS Signature for that JWS.
The RSA SHA256 digital signature for a JWS is validated as follows:
1. Take the Encoded JWS Signature and base64url decode it into a
byte array. If decoding fails, the JWS MUST be rejected.
 2. Submit the bytes of the UTF8 representation of the JWS Secured
 Input (which is the same as the ASCII representation) and the
 public key corresponding to the private key used by the signer to
 the RSASSAPKCS1V1_5VERIFY algorithm using SHA256 as the hash
 function.
+ 2. Submit the bytes of the ASCII representation of the JWS Secured
+ Input and the public key corresponding to the private key used by
+ the signer to the RSASSAPKCS1V1_5VERIFY algorithm using SHA
+ 256 as the hash function.
3. If the validation fails, the JWS MUST be rejected.
Signing with the RSA SHA384 and RSA SHA512 algorithms is performed
 identically to the procedure for RSA SHA256  just with
 correspondingly larger result values.
+ identically to the procedure for RSA SHA256  just using the
+ corresponding hash algorithm with correspondingly larger result
+ values: 384 bits for RSA SHA384 and 512 bits for RSA SHA512.
3.4. Digital Signature with ECDSA P256 SHA256, ECDSA P384 SHA384,
or ECDSA P521 SHA512
 The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined by
 FIPS 1863 [FIPS.1863]. ECDSA provides for the use of Elliptic
 Curve cryptography, which is able to provide equivalent security to
 RSA cryptography but using shorter key sizes and with greater
 processing speed. This means that ECDSA digital signatures will be
 substantially smaller in terms of length than equivalently strong RSA
 digital signatures.
+ The Elliptic Curve Digital Signature Algorithm (ECDSA) [DSS] provides
+ for the use of Elliptic Curve cryptography, which is able to provide
+ equivalent security to RSA cryptography but using shorter key sizes
+ and with greater processing speed. This means that ECDSA digital
+ signatures will be substantially smaller in terms of length than
+ equivalently strong RSA digital signatures.
This specification defines the use of ECDSA with the P256 curve and
the SHA256 cryptographic hash function, ECDSA with the P384 curve
and the SHA384 hash function, and ECDSA with the P521 curve and the
 SHA512 hash function. The P256, P384, and P521 curves are also
 defined in FIPS 1863. The "alg" (algorithm) header parameter values
+ SHA512 hash function. The P256, P384, and P521 curves are
+ defined in [DSS]. The "alg" (algorithm) header parameter values
"ES256", "ES384", and "ES512" are used in the JWS Header to indicate
that the Encoded JWS Signature contains a base64url encoded ECDSA
P256 SHA256, ECDSA P384 SHA384, or ECDSA P521 SHA512 digital
signature, respectively.
 A key of size 160 bits or larger MUST be used with these algorithms.

The ECDSA P256 SHA256 digital signature is generated as follows:
 1. Generate a digital signature of the bytes of the UTF8
 representation of the JWS Secured Input (which is the same as the
 ASCII representation) using ECDSA P256 SHA256 with the desired
 private key. The output will be the EC point (R, S), where R and
 S are unsigned integers.
+ 1. Generate a digital signature of the bytes of the ASCII
+ representation of the JWS Secured Input using ECDSA P256 SHA256
+ with the desired private key. The output will be the EC point
+ (R, S), where R and S are unsigned integers.
 2. Turn R and S into byte arrays in big endian order. Each array
 will be 32 bytes long.
+ 2. Turn R and S into byte arrays in big endian order, with each
+ array being be 32 bytes long.
 3. Concatenate the two byte arrays in the order R and then S.
+ 3. Concatenate the two byte arrays in the order R and then S. (Note
+ that many ECDSA implementations will directly produce this
+ concatenation as their output.)
4. Base64url encode the resulting 64 byte array.
The output is the Encoded JWS Signature for the JWS.
The ECDSA P256 SHA256 digital signature for a JWS is validated as
follows:
1. Take the Encoded JWS Signature and base64url decode it into a
byte array. If decoding fails, the JWS MUST be rejected.
 2. The output of the base64url decoding MUST be a 64 byte array.
+ 2. The output of the base64url decoding MUST be a 64 byte array. If
+ decoding does not result in a 64 byte array, the JWS MUST be
+ rejected.
3. Split the 64 byte array into two 32 byte arrays. The first array
will be R and the second S (with both being in big endian byte
order).
 4. Submit the bytes of the UTF8 representation of the JWS Secured
 Input (which is the same as the ASCII representation), R, S and
 the public key (x, y) to the ECDSA P256 SHA256 validator.
+ 4. Submit the bytes of the ASCII representation of the JWS Secured
+ Input R, S and the public key (x, y) to the ECDSA P256 SHA256
+ validator.
5. If the validation fails, the JWS MUST be rejected.
 The ECDSA validator will then determine if the digital signature is
 valid, given the inputs. Note that ECDSA digital signature contains
 a value referred to as K, which is a random number generated for each
 digital signature instance. This means that two ECDSA digital
 signatures using exactly the same input parameters will output
 different signature values because their K values will be different.
 The consequence of this is that one must validate an ECDSA digital
 signature by submitting the previously specified inputs to an ECDSA
 validator.
+ Note that ECDSA digital signature contains a value referred to as K,
+ which is a random number generated for each digital signature
+ instance. This means that two ECDSA digital signatures using exactly
+ the same input parameters will output different signature values
+ because their K values will be different. A consequence of this is
+ that one cannot validate an ECDSA signature by recomputing the
+ signature and comparing the results.
Signing with the ECDSA P384 SHA384 and ECDSA P521 SHA512
algorithms is performed identically to the procedure for ECDSA P256
 SHA256  just with correspondingly larger result values.
+ SHA256  just using the corresponding hash algorithm with
+ correspondingly larger result values. For ECDSA P384 SHA384, R and
+ S will be 48 bytes each, resulting in a 96 byte array. For ECDSA
+ P521 SHA512, R and S will be 66 bytes each (so they can represent a
+ 521bit integer), resulting in a 132 byte array.
3.5. Creating a Plaintext JWS
+3.5. Using the Algorithm "none"
 To support use cases where the content is secured by a means other
 than a digital signature or MAC value, JWSs MAY also be created
 without them. These are called "Plaintext JWSs". Plaintext JWSs
 MUST use the "alg" value "none", and are formatted identically to
 other JWSs, but with an empty JWS Signature value.
+ JWSs MAY also be created that do not provide integrity protection.
+ Such a JWS is called a "Plaintext JWS". Plaintext JWSs MUST use the
+ "alg" value "none", and are formatted identically to other JWSs, but
+ with an empty JWS Signature value.
3.6. Additional Digital Signature/MAC Algorithms and Parameters
Additional algorithms MAY be used to protect JWSs with corresponding
"alg" (algorithm) header parameter values being defined to refer to
 them. New "alg" header parameter values SHOULD either be defined in
 the IANA JSON Web Signature and Encryption Algorithms registry
 Section 6.2 or be a URI that contains a collision resistant
 namespace. In particular, it is permissible to use the algorithm
+ them. New "alg" header parameter values SHOULD either be registered
+ in the IANA JSON Web Signature and Encryption Algorithms registry
+ Section 6.1 or be a URI that contains a Collision Resistant
+ Namespace. In particular, it is permissible to use the algorithm
identifiers defined in XML DSIG [RFC3275], XML DSIG 2.0
[W3C.CRxmldsigcore220120124], and related specifications as "alg"
values.
As indicated by the common registry, JWSs and JWEs share a common
"alg" value space. The values used by the two specifications MUST be
distinct, as the "alg" value MAY be used to determine whether the
object is a JWS or JWE.
Likewise, additional reserved header parameter names MAY be defined
via the IANA JSON Web Signature and Encryption Header Parameters
 registry Section 6.1. As indicated by the common registry, JWSs and
 JWEs share a common header parameter space; when a parameter is used
 by both specifications, its usage must be compatible between the
+ registry [JWS]. As indicated by the common registry, JWSs and JWEs
+ share a common header parameter space; when a parameter is used by
+ both specifications, its usage must be compatible between the
specifications.
4. Cryptographic Algorithms for JWE
JWE uses cryptographic algorithms to encrypt the Content Master Key
(CMK) and the Plaintext. This section specifies a set of specific
algorithms for these purposes.
4.1. "alg" (Algorithm) Header Parameter Values for JWE
The table below is the set of "alg" (algorithm) header parameter
values that are defined by this specification for use with JWE.
These algorithms are used to encrypt the CMK, producing the JWE
Encrypted Key, or to use key agreement to agree upon the CMK.
 +++
  alg  Key Encryption or Agreement Algorithm 
  Parameter  
  Value  
 +++
  RSA1_5  RSA using RSAPKCS11.5 padding, as defined in RFC 
   3447 [RFC3447] 
  RSAOAEP  RSA using Optimal Asymmetric Encryption Padding 
   (OAEP), as defined in RFC 3447 [RFC3447] 
  ECDHES  Elliptic Curve DiffieHellman Ephemeral Static, as 
   defined in RFC 6090 [RFC6090], and using the Concat 
   KDF, as defined in Section 5.8.1 of [NIST.80056A], 
   where the Digest Method is SHA256 and all OtherInfo 
   parameters are the empty bit string 
  A128KW  Advanced Encryption Standard (AES) Key Wrap Algorithm 
   using 128 bit keys, as defined in RFC 3394 [RFC3394] 
  A256KW  Advanced Encryption Standard (AES) Key Wrap Algorithm 
   using 256 bit keys, as defined in RFC 3394 [RFC3394] 
 +++
+ ++++
+  alg  Key Encryption or Agreement  Implementation 
+  Parameter  Algorithm  Requirements 
+  Value   
+ ++++
+  RSA1_5  RSAESPKCS1V1_5 [RFC3447]  REQUIRED 
+  RSAOAEP  RSAES using Optimal Asymmetric  OPTIONAL 
+   Encryption Padding (OAEP) [RFC3447],  
+   with the default parameters  
+   specified by RFC 3447 in Section  
+   A.2.1  
+  ECDHES  Elliptic Curve DiffieHellman  RECOMMENDED+ 
+   Ephemeral Static [RFC6090], and  
+   using the Concat KDF, as defined in  
+   Section 5.8.1 of [NIST.80056A],  
+   where the Digest Method is SHA256  
+   and all OtherInfo parameters are the  
+   empty bit string  
+  A128KW  Advanced Encryption Standard (AES)  RECOMMENDED 
+   Key Wrap Algorithm [RFC3394] using  
+   128 bit keys  
+  A256KW  AES Key Wrap Algorithm using 256 bit  RECOMMENDED 
+   keys  
+ ++++
+
+ The use of "+" in the Implementation Requirements indicates that the
+ requirement strength is likely to be increased in a future version of
+ the specification.
4.2. "enc" (Encryption Method) Header Parameter Values for JWE
The table below is the set of "enc" (encryption method) header
parameter values that are defined by this specification for use with
JWE. These algorithms are used to encrypt the Plaintext, which
produces the Ciphertext.
 +++
  enc  Block Encryption Algorithm 
  Parameter  
  Value  
 +++
  A128CBC  Advanced Encryption Standard (AES) using 128 bit keys 
   in Cipher Block Chaining (CBC) mode using PKCS #5 
   padding, as defined in [FIPS.197] and [NIST.80038A] 
  A256CBC  Advanced Encryption Standard (AES) using 256 bit keys 
   in Cipher Block Chaining (CBC) mode using PKCS #5 
   padding, as defined in [FIPS.197] and [NIST.80038A] 
  A128GCM  Advanced Encryption Standard (AES) using 128 bit keys 
   in Galois/Counter Mode (GCM), as defined in 
   [FIPS.197] and [NIST.80038D] 
  A256GCM  Advanced Encryption Standard (AES) using 256 bit keys 
   in Galois/Counter Mode (GCM), as defined in 
   [FIPS.197] and [NIST.80038D] 
 +++
+ ++++
+  enc  Block Encryption Algorithm  Implementation 
+  Parameter   Requirements 
+  Value   
+ ++++
+  A128CBC  Advanced Encryption Standard (AES)  REQUIRED 
+   in Cipher Block Chaining (CBC) mode  
+   with PKCS #5 padding [AES]  
+   [NIST.80038A] using 128 bit keys  
+  A256CBC  AES in CBC mode with PKCS #5 padding  REQUIRED 
+   using 256 bit keys  
+  A128GCM  AES in Galois/Counter Mode (GCM)  RECOMMENDED 
+   [AES] [NIST.80038D] using 128 bit  
+   keys  
+  A256GCM  AES GCM using 256 bit keys  RECOMMENDED 
+ ++++
+
+ All the names are short because a core goal of JWE is for the
+ representations to be compact. However, there is no a priori length
+ restriction on "alg" values.
See Appendix B for a table crossreferencing the encryption "alg"
(algorithm) and "enc" (encryption method) values used in this
specification with the equivalent identifiers used by other standards
and software packages.
 Of these "alg" and "enc" algorithms, only RSAPKCS11.5 with 2048 bit
 keys, AES128KW, AES256KW, AES128CBC, and AES256CBC MUST be
 implemented by conforming JWE implementations. It is RECOMMENDED
 that implementations also support ECDHES with 256 bit keys, AES128
 GCM, and AES256GCM. Support for other algorithms and key sizes is
 OPTIONAL.

4.3. "int" (Integrity Algorithm) Header Parameter Values for JWE
The table below is the set of "int" (integrity algorithm) header
parameter values defined by this specification for use with JWE.
Note that these are the HMAC SHA subset of the "alg" (algorithm)
 header parameter values defined for use with JWS Section 3.1. />
+ header parameter values defined for use with JWS Section 3.1.
 +++
  int Parameter Value  Algorithm 
 +++
  HS256  HMAC using SHA256 hash algorithm 
  HS384  HMAC using SHA384 hash algorithm 
  HS512  HMAC using SHA512 hash algorithm 
 +++
+ ++++
+  int Parameter  Algorithm  Implementation 
+  Value   Requirements 
+ ++++
+  HS256  HMAC using SHA256 hash  REQUIRED 
+   algorithm  
+  HS384  HMAC using SHA384 hash  OPTIONAL 
+   algorithm  
+  HS512  HMAC using SHA512 hash  OPTIONAL 
+   algorithm  
+ ++++
 Of these "int" algorithms, only HMAC SHA256 MUST be implemented by
 conforming JWE implementations. It is RECOMMENDED that
 implementations also support the RSA SHA256 and ECDSA P256 SHA256
 algorithms.
+4.4. "kdf" (Key Derivation Function) Header Parameter Values for JWE
4.4. Key Encryption with RSA using RSAPKCS11.5 Padding
+ The table below is the set of "kdf" (key derivation function) header
+ parameter values defined by this specification for use with JWE.
 This section defines the specifics of encrypting a JWE CMK with RSA
 using RSAPKCS11.5 padding, as defined in RFC 3447 [RFC3447]. The
 "alg" header parameter value "RSA1_5" is used in this case.
+ ++++
+  kdf  Algorithm  Implementation 
+  Parameter   Requirements 
+  Value   
+ ++++
+  CS256  Concat KDF, as defined in Section  REQUIRED 
+   5.8.1 of [NIST.80056A], with  
+   parameters per Section 4.12, using  
+   SHA256 as the digest method  
+  CS384  Concat KDF with parameters per  OPTIONAL 
+   Section 4.12, using SHA384 as the  
+   digest method  
+  CS512  Concat KDF with parameters per  OPTIONAL 
+   Section 4.12, using SHA512 as the  
+   digest method  
+ ++++
+
+4.5. Key Encryption with RSAESPKCS1V1_5
+
+ This section defines the specifics of encrypting a JWE CMK with
+ RSAESPKCS1V1_5 [RFC3447]. The "alg" header parameter value
+ "RSA1_5" is used in this case.
A key of size 2048 bits or larger MUST be used with this algorithm.
4.5. Key Encryption with RSA using Optimal Asymmetric Encryption
 Padding (OAEP)
+4.6. Key Encryption with RSAES OAEP
 This section defines the specifics of encrypting a JWE CMK with RSA
 using Optimal Asymmetric Encryption Padding (OAEP), as defined in RFC
 3447 [RFC3447]. The "alg" header parameter value "RSAOAEP" is used
 in this case.
+ This section defines the specifics of encrypting a JWE CMK with RSAES
+ using Optimal Asymmetric Encryption Padding (OAEP) [RFC3447], with
+ the default parameters specified by RFC 3447 in Section A.2.1. The
+ "alg" header parameter value "RSAOAEP" is used in this case.
A key of size 2048 bits or larger MUST be used with this algorithm.
4.6. Key Agreement with Elliptic Curve DiffieHellman Ephemeral Static
+4.7. Key Agreement with Elliptic Curve DiffieHellman Ephemeral Static
(ECDHES)
This section defines the specifics of agreeing upon a JWE CMK with
 Elliptic Curve DiffieHellman Ephemeral Static, as defined in RFC
 6090 [RFC6090], and using the Concat KDF, as defined in Section 5.8.1
 of [NIST.80056A], where the Digest Method is SHA256 and all
 OtherInfo parameters are the empty bit string. The "alg" header
 parameter value "ECDHES" is used in this case.
+ Elliptic Curve DiffieHellman Ephemeral Static [RFC6090], and using
+ the Concat KDF, as defined in Section 5.8.1 of [NIST.80056A], where
+ the Digest Method is SHA256 and all OtherInfo parameters are the
+ empty bit string. The "alg" header parameter value "ECDHES" is used
+ in this case.
 A key of size 160 bits or larger MUST be used for the Elliptic Curve
 keys used with this algorithm. The output of the Concat KDF MUST be
 a key of the same length as that used by the "enc" algorithm.
+ The output of the Concat KDF MUST be a key of the same length as that
+ used by the "enc" algorithm.
 An "epk" (ephemeral public key) value MUST only be used for a single
+ A new "epk" (ephemeral public key) value MUST be generated for each
key agreement transaction.
4.7. Key Encryption with AES Key Wrap
+4.8. Key Encryption with AES Key Wrap
This section defines the specifics of encrypting a JWE CMK with the
 Advanced Encryption Standard (AES) Key Wrap Algorithm using 128 or
 256 bit keys, as defined in RFC 3394 [RFC3394]. The "alg" header
 parameter values "A128KW" or "A256KW" are used in this case.
+ Advanced Encryption Standard (AES) Key Wrap Algorithm [RFC3394] using
+ 128 or 256 bit keys. The "alg" header parameter values "A128KW" or
+ "A256KW" are used in this case.
4.8. Plaintext Encryption with AES Cipher Block Chaining (CBC) Mode
+4.9. Plaintext Encryption with AES CBC Mode
This section defines the specifics of encrypting the JWE Plaintext
with Advanced Encryption Standard (AES) in Cipher Block Chaining
 (CBC) mode using PKCS #5 padding using 128 or 256 bit keys, as
 defined in [FIPS.197] and [NIST.80038A]. The "enc" header parameter
 values "A128CBC" or "A256CBC" are used in this case.
+ (CBC) mode with PKCS #5 padding [AES] [NIST.80038A] using 128 or 256
+ bit keys. The "enc" header parameter values "A128CBC" or "A256CBC"
+ are used in this case.
 Use of an Initialization Vector (IV) of size 128 bits is RECOMMENDED
 with this algorithm.
+ Use of an initialization vector of size 128 bits is REQUIRED with
+ this algorithm.
4.9. Plaintext Encryption with AES Galois/Counter Mode (GCM)
+4.10. Plaintext Encryption with AES GCM
This section defines the specifics of encrypting the JWE Plaintext
with Advanced Encryption Standard (AES) in Galois/Counter Mode (GCM)
 using 128 or 256 bit keys, as defined in [FIPS.197] and
 [NIST.80038D]. The "enc" header parameter values "A128GCM" or
 "A256GCM" are used in this case.
+ [AES] [NIST.80038D] using 128 or 256 bit keys. The "enc" header
+ parameter values "A128GCM" or "A256GCM" are used in this case.
 Use of an Initialization Vector (IV) of size 96 bits is REQUIRED with
 this algorithm.
+ Use of an initialization vector of size 96 bits is REQUIRED with this
+ algorithm.
 The "additional authenticated data" parameter value for the
 encryption is the concatenation of the Encoded JWE Header, a period
 ('.') character, and the Encoded JWE Encrypted Key.
+ The "additional authenticated data" parameter is used to secure the
+ header and key values, as specified for AEAD algorithms in Section 5
+ of [JWE].
 The requested size of the "authentication tag" output MUST be the
 same as the key size (for instance, 128 bits for "A128GCM").
+ The requested size of the "authentication tag" output MUST be 128
+ bits, regardless of the key size.
As GCM is an AEAD algorithm, the JWE Integrity Value is set to be the
"authentication tag" value produced by the encryption.
4.10. Integrity Calculation with HMAC SHA256, HMAC SHA384, or HMAC
+4.11. Integrity Calculation with HMAC SHA256, HMAC SHA384, or HMAC
SHA512
This section defines the specifics of computing a JWE Integrity Value
 with HMAC SHA256, HMAC SHA384, or HMAC SHA512 as defined in FIPS
 1803 [FIPS.1803]. The "int" header parameter values "HS256",
 "HS384", or "HS512" are used in this case.
+ with HMAC SHA256, HMAC SHA384, or HMAC SHA512 [SHS]. Other than
+ as stated below, these computations are performed identically to
+ those specified in Section 3.2.
A key of the same size as the hash output (for instance, 256 bits for
 "HS256") or larger MUST be used with this algorithm.
+ "HS256") MUST be used with this algorithm.
4.11. Additional Encryption Algorithms and Parameters
+ Per Section 9 of [JWE], the JWS Secured Input value used contains the
+ header, encrypted key, and ciphertext.
+
+4.12. Key Derivation with Concat KDF and SHA256, SHA384, or SHA512
+
+ The key derivation process derives CEK and CIK values from the CMK.
+ It uses as a primitive a Key Derivation Function (KDF) which
+ notionally takes three arguments:
+
+ MasterKey: The master key used to compute the individual use keys
+ Label: The use key label, used to differentiate individual use keys
+
+ Length: The desired length of the use key
+
+ This section defines the specifics of using the Concat KDF, as
+ defined in Section 5.8.1 of [NIST.80056A], where the Digest Method
+ is one of SHA256, SHA384, or SHA512, the SuppPubInfo parameter is
+ the Label, and the remaining OtherInfo parameters are the empty bit
+ string.
+
+ The "kdf" (key derivation function) header parameter values "CS256",
+ "CS384", and "CS512" are respectively used in the JWE Header to
+ indicate the use of the Concat KDF as above with the respective
+ digest methods. If the "kdf" header parameter is omitted when an
+ AEAD "enc" algorithm is not used, this is equivalent to specifying
+ use of the "CS256" key derivation function.
+
+ To compute the CEK from the CMK, the ASCII label "Encryption" ([69,
+ 110, 99, 114, 121, 112, 116, 105, 111, 110]) is used. Use the key
+ size for the "enc" algorithm as the CEK desired key length.
+
+ To compute the CIK from the CMK, the ASCII label "Integrity" ([73,
+ 110, 116, 101, 103, 114, 105, 116, 121]) is used. Use the minimum
+ key size for the "int" algorithm (for instance, 256 bits for "HS256")
+ as the CIK desired key length.
+
+4.13. Additional Encryption Algorithms and Parameters
Additional algorithms MAY be used to protect JWEs with corresponding
"alg" (algorithm), "enc" (encryption method), and "int" (integrity
algorithm) header parameter values being defined to refer to them.
New "alg", "enc", and "int" header parameter values SHOULD either be
 defined in the IANA JSON Web Signature and Encryption Algorithms
 registry Section 6.2 or be a URI that contains a collision resistant
 namespace. In particular, it is permissible to use the algorithm
+ registered in the IANA JSON Web Signature and Encryption Algorithms
+ registry Section 6.1 or be a URI that contains a Collision Resistant
+ Namespace. In particular, it is permissible to use the algorithm
identifiers defined in XML Encryption [W3C.RECxmlenccore20021210],
XML Encryption 1.1 [W3C.CRxmlenccore120120313], and related
specifications as "alg", "enc", and "int" values.
As indicated by the common registry, JWSs and JWEs share a common
"alg" value space. The values used by the two specifications MUST be
distinct, as the "alg" value MAY be used to determine whether the
object is a JWS or JWE.
Likewise, additional reserved header parameter names MAY be defined
via the IANA JSON Web Signature and Encryption Header Parameters
 registry Section 6.1. As indicated by the common registry, JWSs and
 JWEs share a common header parameter space; when a parameter is used
 by both specifications, its usage must be compatible between the
+ registry [JWS]. As indicated by the common registry, JWSs and JWEs
+ share a common header parameter space; when a parameter is used by
+ both specifications, its usage must be compatible between the
specifications.
5. Cryptographic Algorithms for JWK
 A JSON Web Key (JWK) [JWK] is a JSON data structure that represents a
 public key. A JSON Web Key Set (JWK Set) is a JSON data structure
 for representing a set of JWKs. This section specifies a set of
 algorithm families to be used for those public keys and the algorithm
 family specific parameters for representing those keys.
+ A JSON Web Key (JWK) [JWK] is a JavaScript Object Notation (JSON)
+ [RFC4627] data structure that represents a public key. A JSON Web
+ Key Set (JWK Set) is a JSON data structure for representing a set of
+ JWKs. This section specifies a set of algorithm families to be used
+ for those public keys and the algorithm family specific parameters
+ for representing those keys.
5.1. "alg" (Algorithm Family) Parameter Values for JWK
The table below is the set of "alg" (algorithm family) parameter
values that are defined by this specification for use in JWKs.
 +++
  alg Parameter Value  Algorithm Family 
 +++
  EC  Elliptic Curve [FIPS.1863] key family 
  RSA  RSA [RFC3447] key family 
 +++
+ ++++
+  alg Parameter  Algorithm Family  Implementation 
+  Value   Requirements 
+ ++++
+  EC  Elliptic Curve [DSS]  RECOMMENDED+ 
+   key family  
+  RSA  RSA [RFC3447] key  REQUIRED 
+   family  
+ ++++
+
+ All the names are short because a core goal of JWK is for the
+ representations to be compact. However, there is no a priori length
+ restriction on "alg" values.
+
+ The use of "+" in the Implementation Requirements indicates that the
+ requirement strength is likely to be increased in a future version of
+ the specification.
5.2. JWK Parameters for Elliptic Curve Keys
 JWKs can represent Elliptic Curve [FIPS.1863] keys. In this case,
 the "alg" member value MUST be "EC". Furthermore, these additional
+ JWKs can represent Elliptic Curve [DSS] keys. In this case, the
+ "alg" member value MUST be "EC". Furthermore, these additional
members MUST be present:
5.2.1. "crv" (Curve) Parameter
The "crv" (curve) member identifies the cryptographic curve used with
 the key. Values defined by this specification are "P256", "P384"
 and "P521". Additional "crv" values MAY be used, provided they are
 understood by implementations using that Elliptic Curve key. The
 "crv" value is case sensitive. Its value MUST be a string.
+ the key. Curve values from [DSS] used by this specification are:
+
+ o "P256"
+
+ o "P384"
+
+ o "P521"
+
+ Additional "crv" values MAY be used, provided they are understood by
+ implementations using that Elliptic Curve key. The "crv" value is
+ case sensitive. Its value MUST be a string.
5.2.2. "x" (X Coordinate) Parameter
The "x" (x coordinate) member contains the x coordinate for the
elliptic curve point. It is represented as the base64url encoding of
the coordinate's big endian representation.
5.2.3. "y" (Y Coordinate) Parameter
The "y" (y coordinate) member contains the y coordinate for the
@@ 632,184 +841,570 @@
5.3. JWK Parameters for RSA Keys
JWKs can represent RSA [RFC3447] keys. In this case, the "alg"
member value MUST be "RSA". Furthermore, these additional members
MUST be present:
5.3.1. "mod" (Modulus) Parameter
The "mod" (modulus) member contains the modulus value for the RSA
public key. It is represented as the base64url encoding of the
 value's big endian representation.
+ value's unsigned big endian representation.
5.3.2. "exp" (Exponent) Parameter
The "exp" (exponent) member contains the exponent value for the RSA
public key. It is represented as the base64url encoding of the
 value's big endian representation.
+ value's unsigned big endian representation.
5.4. Additional Key Algorithm Families and Parameters
Public keys using additional algorithm families MAY be represented
using JWK data structures with corresponding "alg" (algorithm family)
parameter values being defined to refer to them. New "alg" parameter
 values SHOULD either be defined in the IANA JSON Web Key Algorithm
 Families registry Section 6.5 or be a URI that contains a collision
 resistant namespace.
+ values SHOULD either be registered in the IANA JSON Web Key Algorithm
+ Families registry Section 6.2 or be a URI that contains a Collision
+ Resistant Namespace.
Likewise, parameters for representing keys for additional algorithm
 families or additional key properties SHOULD either be defined in the
 IANA JSON Web Key Parameters registry Section 6.4 or be a URI that
 contains a collision resistant namespace.
+ families or additional key properties SHOULD either be registered in
+ the IANA JSON Web Key Parameters registry [JWK] or be a URI that
+ contains a Collision Resistant Namespace.
6. IANA Considerations
6.1. JSON Web Signature and Encryption Header Parameters Registry
+ The following registration procedure is used for all the registries
+ established by this specification.
 This specification establishes the IANA JSON Web Signature and
 Encryption Header Parameters registry for reserved JWS and JWE header
 parameter names. Inclusion in the registry is RFC Required in the
 RFC 5226 [RFC5226] sense. The registry records the reserved header
 parameter name and a reference to the RFC that defines it. This
 specification registers the header parameter names defined in JSON
 Web Signature (JWS) [JWS], Section 4.1 and JSON Web Encryption (JWE)
 [JWE], Section 4.1.
+ Values are registered with a Specification Required [RFC5226] after a
+ two week review period on the [TBD]@ietf.org mailing list, on the
+ advice of one or more Designated Experts. However, to allow for the
+ allocation of values prior to publication, the Designated Expert(s)
+ may approve registration once they are satisfied that such a
+ specification will be published.
6.2. JSON Web Signature and Encryption Algorithms Registry
+ Registration requests must be sent to the [TBD]@ietf.org mailing list
+ for review and comment, with an appropriate subject (e.g., "Request
+ for access token type: example"). [[ Note to RFCEDITOR: The name of
+ the mailing list should be determined in consultation with the IESG
+ and IANA. Suggested name: joseregreview. ]]
+
+ Within the review period, the Designated Expert(s) will either
+ approve or deny the registration request, communicating this decision
+ to the review list and IANA. Denials should include an explanation
+ and, if applicable, suggestions as to how to make the request
+ successful.
+
+ IANA must only accept registry updates from the Designated Expert(s),
+ and should direct all requests for registration to the review mailing
+ list.
+
+6.1. JSON Web Signature and Encryption Algorithms Registry
This specification establishes the IANA JSON Web Signature and
Encryption Algorithms registry for values of the JWS and JWE "alg"
(algorithm), "enc" (encryption method), and "int" (integrity
 algorithm) header parameters. Inclusion in the registry is RFC
 Required in the RFC 5226 [RFC5226] sense. The registry records the
 algorithm usage "alg", "enc", or "int", the value, and a pointer to
 the RFC that defines it. This specification registers the values
 defined in Section 3.1, Section 4.1, Section 4.2, and Section 4.3.
+ algorithm) header parameters. The registry records the algorithm
+ name, the algorithm usage locations from the set "alg", "enc", and
+ "int", implementation requirements, and a reference to the
+ specification that defines it. The same algorithm name may be
+ registered multiple times, provided that the sets of usage locations
+ are disjoint. The implementation requirements of an algorithm may be
+ changed over time by the Designated Experts(s) as the cryptographic
+ landscape evolves, for instance, to change the status of an algorithm
+ to DEPRECATED, or to change the status of an algorithm from OPTIONAL
+ to RECOMMENDED or REQUIRED.
6.3. JSON Web Signature and Encryption "typ" Values Registry
+6.1.1. Registration Template
 This specification establishes the IANA JSON Web Signature and
 Encryption "typ" Values registry for values of the JWS and JWE "typ"
 (type) header parameter. Inclusion in the registry is RFC Required
 in the RFC 5226 [RFC5226] sense. It is RECOMMENDED that all
 registered "typ" values also register a MIME Media Type RFC 2045
 [RFC2045] that the registered value is a short name for. The
 registry records the "typ" value, the MIME type value that it is an
 abbreviation for (if any), and a pointer to the RFC that defines it.
+ Algorithm Name:
+ The name requested (e.g., "example").
 MIME Media Type RFC 2045 [RFC2045] values MUST NOT be directly
 registered as new "typ" values; rather, new "typ" values MAY be
 registered as short names for MIME types.
+ Algorithm Usage Location(s):
+ The algorithm usage, which must be one or more of the values
+ "alg", "enc", "int", or "kdf".
6.4. JSON Web Key Parameters Registry
+ Implementation Requirements:
+ The algorithm implementation requirements, which must be one the
+ words REQUIRED, RECOMMENDED, OPTIONAL, or DEPRECATED. Optionally,
+ the word may be followed by a "+" or "". The use of "+"
+ indicates that the requirement strength is likely to be increased
+ in a future version of the specification. The use of ""
+ indicates that the requirement strength is likely to be decreased
+ in a future version of the specification.
 This specification establishes the IANA JSON Web Key Parameters
 registry for reserved JWK parameter names. Inclusion in the registry
 is RFC Required in the RFC 5226 [RFC5226] sense. The registry
 records the reserved parameter name and a reference to the RFC that
 defines it. This specification registers the parameter names defined
 in JSON Web Key (JWK) [JWK], Section 4.2, JSON Web Encryption (JWE)
 [JWE], Section 4.1, Section 5.2, and Section 5.3.
+ Change Controller:
+ For standardstrack RFCs, state "IETF". For others, give the name
+ of the responsible party. Other details (e.g., postal address,
+ email address, home page URI) may also be included.
6.5. JSON Web Key Algorithm Families Registry
+ Specification Document(s):
+ Reference to the document that specifies the parameter, preferably
+ including a URI that can be used to retrieve a copy of the
+ document. An indication of the relevant sections may also be
+ included, but is not required.
+
+6.1.2. Initial Registry Contents
+
+ o Algorithm Name: "HS256"
+
+ o Algorithm Usage Location(s): "alg", "int"
+
+ o Implementation Requirements: REQUIRED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 and Section 4.3 of [[ this
+ document ]]
+
+ o Algorithm Name: "HS384"
+
+ o Algorithm Usage Location(s): "alg", "int"
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 and Section 4.3 of [[ this
+ document ]]
+
+ o Algorithm Name: "HS512"
+
+ o Algorithm Usage Location(s): "alg", "int"
+
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 and Section 4.3 of [[ this
+ document ]]
+
+ o Algorithm Name: "RS256"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: RECOMMENDED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 of [[ this document ]]
+
+ o Algorithm Name: "RS384"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 of [[ this document ]]
+
+ o Algorithm Name: "RS512"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 of [[ this document ]]
+ o Algorithm Name: "ES256"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: RECOMMENDED+
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 of [[ this document ]]
+
+ o Algorithm Name: "ES384"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 of [[ this document ]]
+
+ o Algorithm Name: "ES512"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 of [[ this document ]]
+
+ o Algorithm Name: "none"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: REQUIRED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 3.1 of [[ this document ]]
+
+ o Algorithm Name: "RSA1_5"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: REQUIRED
+
+ o Change Controller: IETF
+ o Specification Document(s): Section 4.1 of [[ this document ]]
+
+ o Algorithm Name: "RSAOAEP"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.1 of [[ this document ]]
+
+ o Algorithm Name: "ECDHES"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: RECOMMENDED+
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.1 of [[ this document ]]
+
+ o Algorithm Name: "A128KW"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: RECOMMENDED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.1 of [[ this document ]]
+
+ o Algorithm Name: "A256KW"
+
+ o Algorithm Usage Location(s): "alg"
+
+ o Implementation Requirements: RECOMMENDED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.1 of [[ this document ]]
+
+ o Algorithm Name: "A128CBC"
+
+ o Algorithm Usage Location(s): "enc"
+
+ o Implementation Requirements: REQUIRED
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.2 of [[ this document ]]
+
+ o Algorithm Name: "A256CBC"
+
+ o Algorithm Usage Location(s): "enc"
+
+ o Implementation Requirements: REQUIRED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.2 of [[ this document ]]
+
+ o Algorithm Name: "A128GCM"
+
+ o Algorithm Usage Location(s): "enc"
+
+ o Implementation Requirements: RECOMMENDED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.2 of [[ this document ]]
+
+ o Algorithm Name: "A256GCM"
+
+ o Algorithm Usage Location(s): "enc"
+
+ o Implementation Requirements: RECOMMENDED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.2 of [[ this document ]]
+
+ o Algorithm Name: "CS256"
+
+ o Algorithm Usage Location(s): "kdf"
+
+ o Implementation Requirements: REQUIRED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.4 of [[ this document ]]
+
+ o Algorithm Name: "CS384"
+
+ o Algorithm Usage Location(s): "kdf"
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.4 of [[ this document ]]
+
+ o Algorithm Name: "CS512"
+
+ o Algorithm Usage Location(s): "kdf"
+
+ o Implementation Requirements: OPTIONAL
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 4.4 of [[ this document ]]
+
+6.2. JSON Web Key Algorithm Families Registry
This specification establishes the IANA JSON Web Key Algorithm
Families registry for values of the JWK "alg" (algorithm family)
 parameter. Inclusion in the registry is RFC Required in the RFC 5226
 [RFC5226] sense. The registry records the "alg" value and a pointer
 to the RFC that defines it. This specification registers the values
 defined in Section 5.1.
+ parameter. The registry records the "alg" value and a reference to
+ the specification that defines it. This specification registers the
+ values defined in Section 5.1.
+
+6.2.1. Registration Template
+
+ "alg" Parameter Value:
+ The name requested (e.g., "example").
+
+ Change Controller:
+ For standardstrack RFCs, state "IETF". For others, give the name
+ of the responsible party. Other details (e.g., postal address,
+ email address, home page URI) may also be included.
+
+ Implementation Requirements:
+ The algorithm implementation requirements, which must be one the
+ words REQUIRED, RECOMMENDED, OPTIONAL, or DEPRECATED. Optionally,
+ the word may be followed by a "+" or "". The use of "+"
+ indicates that the requirement strength is likely to be increased
+ in a future version of the specification. The use of ""
+ indicates that the requirement strength is likely to be decreased
+ in a future version of the specification.
+
+ Specification Document(s):
+ Reference to the document that specifies the parameter, preferably
+ including a URI that can be used to retrieve a copy of the
+ document. An indication of the relevant sections may also be
+ included, but is not required.
+
+6.2.2. Initial Registry Contents
+
+ o "alg" Parameter Value: "EC"
+
+ o Implementation Requirements: RECOMMENDED+
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 5.1 of [[ this document ]]
+
+ o "alg" Parameter Value: "RSA"
+
+ o Implementation Requirements: REQUIRED
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 5.1 of [[ this document ]]
+
+6.3. JSON Web Key Parameters Registration
+
+ This specification registers the parameter names defined in
+ Section 5.2 and Section 5.3 in the IANA JSON Web Key Parameters
+ registry [JWK].
+
+6.3.1. Registry Contents
+
+ o Parameter Name: "crv"
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 5.2.1 of [[ this document ]]
+
+ o Parameter Name: "x"
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 5.2.2 of [[ this document ]]
+
+ o Parameter Name: "y"
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 5.2.3 of [[ this document ]]
+
+ o Parameter Name: "mod"
+
+ o Change Controller: IETF
+ o Specification Document(s): Section 5.3.1 of [[ this document ]]
+
+ o Parameter Name: "exp"
+
+ o Change Controller: IETF
+
+ o Specification Document(s): Section 5.3.2 of [[ this document ]]
7. Security Considerations
 The security considerations in the JWS, JWE, and JWK specifications
 also apply to this specification.
+ All of the security issues faced by any cryptographic application
+ must be faced by a JWS/JWE/JWK agent. Among these issues are
+ protecting the user's private key, preventing various attacks, and
+ helping the user avoid mistakes such as inadvertently encrypting a
+ message for the wrong recipient. The entire list of security
+ considerations is beyond the scope of this document, but some
+ significant concerns are listed here.
+
+ The security considerations in [AES], [DSS], [JWE], [JWK], [JWS],
+ [NIST.80038A], [NIST.80038D], [NIST.80056A], [RFC2104], [RFC3394],
+ [RFC3447], [RFC5116], [RFC6090], and [SHS] apply to this
+ specification.
Eventually the algorithms and/or key sizes currently described in
this specification will no longer be considered sufficiently secure
and will be removed. Therefore, implementers and deployments must be
prepared for this eventuality.
8. Open Issues and Things To Be Done (TBD)
+ Algorithms of matching strength should be used together whenever
+ possible. For instance, when AES Key Wrap is used with a given key
+ size, using the same key size for AES CBC or GCM is recommended.
+ Likewise, when AES CBC is used with a 128 bit key, using HMAC SHA256
+ as the integrity algorithm is recommended, whereas when AES CBC is
+ used with a 256 bit key, using HMAC SHA512 as the integrity
+ algorithm is recommended.
 The following items remain to be done in this draft:
+ While Section 8 of RFC 3447 [RFC3447] explicitly calls for people not
+ to adopt RSASSAPKCS1 for new applications and instead requests that
+ people transition to RSASSAPSS, this specification does include
+ RSASSAPKCS1, for interoperability reasons, because it commonly
+ implemented.
 o Find values for encryption algorithm crossreference table
 currently listed as "TBD" or determine that they do not exist.
+ Keys used with RSAESPKCS1v1_5 must follow the constraints in
+ Section 7.2 of RFC 3447 [RFC3447]. In particular, keys with a low
+ public key exponent value must not be used.
9. References
+ Plaintext JWSs (JWSs that use the "alg" value "none") provide no
+ integrity protection. Thus, they must only be used in contexts where
+ the payload is secured by means other than a digital signature or MAC
+ value, or need not be secured.
9.1. Normative References
+ Receiving agents that validate signatures and sending agents that
+ encrypt messages need to be cautious of cryptographic processing
+ usage when validating signatures and encrypting messages using keys
+ larger than those mandated in this specification. An attacker could
+ send certificates with keys that would result in excessive
+ cryptographic processing, for example, keys larger than those
+ mandated in this specification, which could swamp the processing
+ element. Agents that use such keys without first validating the
+ certificate to a trust anchor are advised to have some sort of
+ cryptographic resource management system to prevent such attacks.
 [FIPS.1803]
 National Institute of Standards and Technology, "Secure
 Hash Standard (SHS)", FIPS PUB 1803, October 2008.
+8. Open Issues
 [FIPS.1863]
 National Institute of Standards and Technology, "Digital
 Signature Standard (DSS)", FIPS PUB 1863, June 2009.
+ [[ to be removed by the RFC editor before publication as an RFC ]]
 [FIPS.197]
 National Institute of Standards and Technology (NIST),
+ The following items remain to be considered or done in this draft:
+
+ o Should we use the "alg" value as the AlgorithmID input to the
+ Concat KDF when doing key agreement? Or is an AlgorithmID value
+ unnecessary in the way that we are using Concat?
+
+ o Should we use the "enc" and "int" values as AlgorithmID inputs to
+ the Concat KDF when doing key derivation? Or is an AlgorithmID
+ value unnecessary in the way that we are using Concat?
+
+ o Do we want to add AES ECB as a (nonauthenticated) key wrap
+ algorithm?
+
+9. References
+
+9.1. Normative References
+
+ [AES] National Institute of Standards and Technology (NIST),
"Advanced Encryption Standard (AES)", FIPS PUB 197,
November 2001.
+ [DSS] National Institute of Standards and Technology, "Digital
+ Signature Standard (DSS)", FIPS PUB 1863, June 2009.
+
[JWE] Jones, M., Rescorla, E., and J. Hildebrand, "JSON Web
 Encryption (JWE)", May 2012.
+ Encryption (JWE)", July 2012.
 [JWK] Jones, M., "JSON Web Key (JWK)", May 2012.
+ [JWK] Jones, M., "JSON Web Key (JWK)", July 2012.
[JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
 Signature (JWS)", May 2012.
+ Signature (JWS)", July 2012.
[NIST.80038A]
National Institute of Standards and Technology (NIST),
"Recommendation for Block Cipher Modes of Operation",
NIST PUB 80038A, December 2001.
[NIST.80038D]
National Institute of Standards and Technology (NIST),
"Recommendation for Block Cipher Modes of Operation:
Galois/Counter Mode (GCM) and GMAC", NIST PUB 80038D,
December 2001.
[NIST.80056A]
National Institute of Standards and Technology (NIST),
"Recommendation for PairWise Key Establishment Schemes
Using Discrete Logarithm Cryptography (Revised)", NIST PUB
80056A, March 2007.
 [RFC2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
 Extensions (MIME) Part One: Format of Internet Message
 Bodies", RFC 2045, November 1996.

[RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed
Hashing for Message Authentication", RFC 2104,
February 1997.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3394] Schaad, J. and R. Housley, "Advanced Encryption Standard
(AES) Key Wrap Algorithm", RFC 3394, September 2002.
[RFC3447] Jonsson, J. and B. Kaliski, "PublicKey Cryptography
Standards (PKCS) #1: RSA Cryptography Specifications
Version 2.1", RFC 3447, February 2003.
+ [RFC3629] Yergeau, F., "UTF8, a transformation format of ISO
+ 10646", STD 63, RFC 3629, November 2003.
+
+ [RFC4627] Crockford, D., "The application/json Media Type for
+ JavaScript Object Notation (JSON)", RFC 4627, July 2006.
+
+ [RFC4648] Josefsson, S., "The Base16, Base32, and Base64 Data
+ Encodings", RFC 4648, October 2006.
+
+ [RFC5116] McGrew, D., "An Interface and Algorithms for Authenticated
+ Encryption", RFC 5116, January 2008.
+
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008.
[RFC6090] McGrew, D., Igoe, K., and M. Salter, "Fundamental Elliptic
Curve Cryptography Algorithms", RFC 6090, February 2011.
+ [SHS] National Institute of Standards and Technology, "Secure
+ Hash Standard (SHS)", FIPS PUB 1803, October 2008.
+
+ [USASCII] American National Standards Institute, "Coded Character
+ Set  7bit American Standard Code for Information
+ Interchange", ANSI X3.4, 1986.
+
9.2. Informative References
[CanvasApp]
Facebook, "Canvas Applications", 2010.
[ID.rescorlajsms]
Rescorla, E. and J. Hildebrand, "JavaScript Message
Security Format", draftrescorlajsms00 (work in
progress), March 2011.
@@ 822,29 +1417,33 @@
September 2010.
[MagicSignatures]
Panzer (editor), J., Laurie, B., and D. Balfanz, "Magic
Signatures", January 2011.
[RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible Markup
Language) XMLSignature Syntax and Processing", RFC 3275,
March 2002.
+ [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
+ Unique IDentifier (UUID) URN Namespace", RFC 4122,
+ July 2005.
+
[W3C.CRxmldsigcore220120124]
 Eastlake, D., Reagle, J., Yiu, K., Solo, D., Datta, P.,
 Hirsch, F., Cantor, S., and T. Roessler, "XML Signature
+ Reagle, J., Solo, D., Datta, P., Hirsch, F., Eastlake, D.,
+ Roessler, T., Cantor, S., and K. Yiu, "XML Signature
Syntax and Processing Version 2.0", World Wide Web
Consortium CR CRxmldsigcore220120124, January 2012,
.
[W3C.CRxmlenccore120120313]
 Eastlake, D., Reagle, J., Roessler, T., and F. Hirsch,
+ Eastlake, D., Reagle, J., Hirsch, F., and T. Roessler,
"XML Encryption Syntax and Processing Version 1.1", World
Wide Web Consortium CR CRxmlenccore120120313,
March 2012,
.
[W3C.RECxmlenccore20021210]
Eastlake, D. and J. Reagle, "XML Encryption Syntax and
Processing", World Wide Web Consortium Recommendation REC
xmlenccore20021210, December 2002,
.
@@ 877,41 +1476,47 @@
 hash     
 algo     
 rithm     
 HMAC  HS5  http://www.w3.org/2001/04/  HmacSHA5  1.2.840.113 
 using  12  xmldsigmore#hmacsha512  12  549.2.11 
 SHA5     
 12     
 hash     
 algo     
 rithm     
  RSA  RS2  http://www.w3.org/2001/04/  SHA256wi  1.2.840.113 
  using  56  xmldsigmore#rsasha256  thRSA  549.1.1.11 
  SHA2     
  56     
  hash     
  algo     
  rithm     
  RSA  RS3  http://www.w3.org/2001/04/  SHA384wi  1.2.840.113 
  using  84  xmldsigmore#rsasha384  thRSA  549.1.1.12 
  SHA3     
  84     
  hash     
  algo     
  rithm     
  RSA  RS5  http://www.w3.org/2001/04/  SHA512wi  1.2.840.113 
  using  12  xmldsigmore#rsasha512  thRSA  549.1.1.13 
  SHA5     
  12     
  hash     
  algo     
  rithm     
+  RSASS  RS2  http://www.w3.org/2001/04/  SHA256wi  1.2.840.113 
+  A  56  xmldsigmore#rsasha256  thRSA  549.1.1.11 
+  usin     
+  gSHA     
+  256     
+  has     
+  h alg     
+  orith     
+  m     
+  RSASS  RS3  http://www.w3.org/2001/04/  SHA384wi  1.2.840.113 
+  A  84  xmldsigmore#rsasha384  thRSA  549.1.1.12 
+  usin     
+  gSHA     
+  384     
+  has     
+  h alg     
+  orith     
+  m     
+  RSASS  RS5  http://www.w3.org/2001/04/  SHA512wi  1.2.840.113 
+  A  12  xmldsigmore#rsasha512  thRSA  549.1.1.13 
+  usin     
+  gSHA     
+  512     
+  has     
+  h alg     
+  orith     
+  m     
 ECDSA  ES2  http://www.w3.org/2001/04/  SHA256wi  1.2.840.100 
 using  56  xmldsigmore#ecdsasha256  thECDSA  45.4.3.2 
 P256     
 curve     
 and     
 SHA2     
 56     
 hash     
 algo     
 rithm     
@@ 941,159 +1546,153 @@
This appendix contains a table crossreferencing the "alg"
(algorithm) and "enc" (encryption method) values used in this
specification with the equivalent identifiers used by other standards
and software packages. See XML Encryption
[W3C.RECxmlenccore20021210], XML Encryption 1.1
[W3C.CRxmlenccore120120313], and Java Cryptography Architecture
[JCA] for more information about the names defined by those
documents.
 +++++
  Algorit  JWE  XML ENC  JCA 
  hm    
 +++++
  RSA  RSA1_  http://www.w3.org/2001/04  RSA/ECB/PKCS1Paddin 
  using  5  /xmlenc#rsa1_5  g 
  RSAPKC    
  S11.5    
  paddin    
  g    
  RSA  RSAO  http://www.w3.org/2001/04  RSA/ECB/OAEPWithSHA 
  using  AEP  /xmlenc#rsaoaepmgf1p  1AndMGF1Padding 
+ +++++
+  Algorith  JWE  XML ENC  JCA 
+  m    
+ +++++
+  RSAESPK  RSA1  http://www.w3.org/2001/04  RSA/None/PKCS1Paddi 
+  CS1V1_5  _5  /xmlenc#rsa1_5  ng 
+  RSAES  RSA  http://www.w3.org/2001/04  RSA/None/OAEPWithSH 
+  using  OAEP  /xmlenc#rsaoaepmgf1p  A1AndMGF1Padding 
 Optimal    
  Asymmet    
  ric    
  Encryp    
  tion    
  Paddi    
  ng(OAEP    
  )    
  Ellipti  ECDH  http://www.w3.org/2009/xm  TBD 
  cCurve  ES  lenc11#ECDHES  
  Diffie    
  Hellma    
  n Ephem    
  eral    
  Stat    
+  Asymmetr    
 ic    
  Advance  A128K  http://www.w3.org/2001/04  TBD 
  d  W  /xmlenc#kwaes128  
  Encryp    
  tion    
  Stand    
  ard(AES    
  ) Key    
  Wrap    
  Algo    
  rithm R    
  FC 339    
  4 [RF    
  C3394]    
  using12    
  8 bitke    
  ys    
  Advance  A256K  http://www.w3.org/2001/04  TBD 
  d  W  /xmlenc#kwaes256  
  Encryp    
  tion    
  Stand    
  ard(AES    
  ) Key    
  Wrap    
  Algo    
  rithm R    
  FC 339    
  4 [RF    
  C3394]    
  using25    
  6 bitke    
  ys    
  Advance  A128C  http://www.w3.org/2001/04  AES/CBC/PKCS5Paddin 
  d  BC  /xmlenc#aes128cbc  g 
  Encryp    
  tion    
  Stand    
  ard(AES    
  ) usin    
  g 128    
  bitkeys    
  inCiph    
  er Bloc    
  k Chai    
  ning(CB    
  C) mod    
  e usi    
  ng PKC    
  S #5pad    
  ding    
  Advance  A256C  http://www.w3.org/2001/04  AES/CBC/PKCS5Paddin 
  d  BC  /xmlenc#aes256cbc  g 
  Encryp    
  tion    
  Stand    
  ard(AES    
  ) usin    
  g 256    
  bitkeys    
  inCiph    
  er Bloc    
  k Chai    
  ning(CB    
  C) mod    
  e usi    
  ng PKC    
  S #5pad    
  ding    
  Advance  A128G  http://www.w3.org/2009/xm  AES/GCM/NoPadding 
  d  CM  lenc11#aes128gcm  
  Encryp    
  tion    
  Stand    
  ard(AES    
  ) usin    
  g 128    
  bitkeys    
  inGalo    
  is/Coun    
  ter Mod    
  e (GC    
  M)    
  Advance  A256G  http://www.w3.org/2009/xm  AES/GCM/NoPadding 
  d  CM  lenc11#aes256gcm  
  Encryp    
  tion    
  Stand    
  ard(AES    
  ) usin    
  g 256    
  bitkeys    
  inGalo    
  is/Coun    
  ter Mod    
  e (GC    
  M)    
 +++++
+  Encrypt    
+  ion    
+  Paddin    
+  g (OAEP)    
+  Elliptic  ECDH  http://www.w3.org/2009/xm  
+  Curve  ES  lenc11#ECDHES  
+  DiffieH    
+  ellman    
+  Ephemer    
+  alStatic    
+  Advanced  A128  http://www.w3.org/2001/04  
+  Encrypti  KW  /xmlenc#kwaes128  
+  on    
+  Standar    
+  d(AES)    
+  Key Wra    
+  pAlgorit    
+  hmusing    
+  128 bi    
+  t keys    
+  AES Key  A256  http://www.w3.org/2001/04  
+  Wrap  KW  /xmlenc#kwaes256  
+  Algorith    
+  musing    
+  256 bit    
+  keys    
+  AES in  A128  http://www.w3.org/2001/04  AES/CBC/PKCS5Paddin 
+  Cipher  CBC  /xmlenc#aes128cbc  g 
+  Block    
+  Chaining    
+  (CBC)    
+  mode    
+  with    
+  PKCS #5    
+  padding    
+  using    
+  128 bit    
+  keys    
+  AES in  A256  http://www.w3.org/2001/04  AES/CBC/PKCS5Paddin 
+  CBC mode  CBC  /xmlenc#aes256cbc  g 
+  with    
+  PKCS #5    
+  padding    
+  using    
+  256 bit    
+  keys    
+  AES in  A128  http://www.w3.org/2009/xm  AES/GCM/NoPadding 
+  Galois/C  GCM  lenc11#aes128gcm  
+  ounter    
+  Mode    
+  (GCM)    
+  using    
+  128 bit    
+  keys    
+  AES GCM  A256  http://www.w3.org/2009/xm  AES/GCM/NoPadding 
+  using  GCM  lenc11#aes256gcm  
+  256 bit    
+  keys    
+ +++++
Appendix C. Acknowledgements
Solutions for signing and encrypting JSON content were previously
explored by Magic Signatures [MagicSignatures], JSON Simple Sign
[JSS], Canvas Applications [CanvasApp], JSON Simple Encryption [JSE],
and JavaScript Message Security Format [ID.rescorlajsms], all of
which influenced this draft. Dirk Balfanz, John Bradley, Yaron Y.
Goland, John Panzer, Nat Sakimura, and Paul Tarjan all made
significant contributions to the design of this specification and its
related specifications.
Appendix D. Document History
+ [[ to be removed by the RFC editor before publication as an RFC ]]
+
+ 03
+
+ o Always use a 128 bit "authentication tag" size for AES GCM,
+ regardless of the key size.
+
+ o Specified that use of a 128 bit IV is REQUIRED with AES CBC. It
+ was previously RECOMMENDED.
+
+ o Removed key size language for ECDSA algorithms, since the key size
+ is implied by the algorithm being used.
+
+ o Stated that the "int" key size must be the same as the hash output
+ size (and not larger, as was previously allowed) so that its size
+ is defined for key generation purposes.
+
+ o Added the "kdf" (key derivation function) header parameter to
+ provide crypto agility for key derivation. The default KDF
+ remains the Concat KDF with the SHA256 digest function.
+
+ o Clarified that the "mod" and "exp" values are unsigned.
+
+ o Added Implementation Requirements columns to algorithm tables and
+ Implementation Requirements entries to algorithm registries.
+
+ o Changed AES Key Wrap to RECOMMENDED.
+
+ o Moved registries JSON Web Signature and Encryption Header
+ Parameters and JSON Web Signature and Encryption Type Values to
+ the JWS specification.
+
+ o Moved JSON Web Key Parameters registry to the JWK specification.
+
+ o Changed registration requirements from RFC Required to
+ Specification Required with Expert Review.
+
+ o Added Registration Template sections for defined registries.
+
+ o Added Registry Contents sections to populate registry values.
+
+ o No longer say "the UTF8 representation of the JWS Secured Input
+ (which is the same as the ASCII representation)". Just call it
+ "the ASCII representation of the JWS Secured Input".
+
+ o Added "Collision Resistant Namespace" to the terminology section.
+
+ o Numerous editorial improvements.
+
02
o For AES GCM, use the "additional authenticated data" parameter to
provide integrity for the header, encrypted key, and ciphertext
and use the resulting "authentication tag" value as the JWE
Integrity Value.
o Defined minimum required key sizes for algorithms without
specified key sizes.