draft-ietf-jose-json-web-algorithms-01.txt   draft-ietf-jose-json-web-algorithms-02.txt 
JOSE Working Group M. Jones JOSE Working Group M. Jones
Internet-Draft Microsoft Internet-Draft Microsoft
Intended status: Standards Track March 12, 2012 Intended status: Standards Track May 12, 2012
Expires: September 13, 2012 Expires: November 13, 2012
JSON Web Algorithms (JWA) JSON Web Algorithms (JWA)
draft-ietf-jose-json-web-algorithms-01 draft-ietf-jose-json-web-algorithms-02
Abstract Abstract
The JSON Web Algorithms (JWA) specification enumerates cryptographic The JSON Web Algorithms (JWA) specification enumerates cryptographic
algorithms and identifiers to be used with the JSON Web Signature algorithms and identifiers to be used with the JSON Web Signature
(JWS) and JSON Web Encryption (JWE) specifications. (JWS) and JSON Web Encryption (JWE) specifications.
Requirements Language Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
skipping to change at page 1, line 38 skipping to change at page 1, line 38
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 13, 2012. This Internet-Draft will expire on November 13, 2012.
Copyright Notice Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
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described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Cryptographic Algorithms for JWS . . . . . . . . . . . . . . . 3 3. Cryptographic Algorithms for JWS . . . . . . . . . . . . . . . 4
3.1. Creating a JWS with HMAC SHA-256, HMAC SHA-384, or 3.1. "alg" (Algorithm) Header Parameter Values for JWS . . . . 4
HMAC SHA-512 . . . . . . . . . . . . . . . . . . . . . . . 4 3.2. MAC with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 . . . 5
3.2. Creating a JWS with RSA SHA-256, RSA SHA-384, or RSA 3.3. Digital Signature with RSA SHA-256, RSA SHA-384, or
SHA-512 . . . . . . . . . . . . . . . . . . . . . . . . . 5 RSA SHA-512 . . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Creating a JWS with ECDSA P-256 SHA-256, ECDSA P-384 3.4. Digital Signature with ECDSA P-256 SHA-256, ECDSA
SHA-384, or ECDSA P-521 SHA-512 . . . . . . . . . . . . . 6 P-384 SHA-384, or ECDSA P-521 SHA-512 . . . . . . . . . . 7
3.4. Creating a Plaintext JWS . . . . . . . . . . . . . . . . . 7 3.5. Creating a Plaintext JWS . . . . . . . . . . . . . . . . . 9
3.5. Additional Digital Signature/HMAC Algorithms . . . . . . . 7 3.6. Additional Digital Signature/MAC Algorithms and
4. Cryptographic Algorithms for JWE . . . . . . . . . . . . . . . 8 Parameters . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Encrypting a JWE with TBD . . . . . . . . . . . . . . . . 9 4. Cryptographic Algorithms for JWE . . . . . . . . . . . . . . . 9
4.2. Additional Encryption Algorithms . . . . . . . . . . . . . 9 4.1. "alg" (Algorithm) Header Parameter Values for JWE . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 4.2. "enc" (Encryption Method) Header Parameter Values for
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 JWE . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
7. Open Issues and Things To Be Done (TBD) . . . . . . . . . . . 10 4.3. "int" (Integrity Algorithm) Header Parameter Values
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 11 for JWE . . . . . . . . . . . . . . . . . . . . . . . . . 11
8.1. Normative References . . . . . . . . . . . . . . . . . . . 11 4.4. Key Encryption with RSA using RSA-PKCS1-1.5 Padding . . . 11
8.2. Informative References . . . . . . . . . . . . . . . . . . 12 4.5. Key Encryption with RSA using Optimal Asymmetric
Appendix A. Digital Signature/HMAC Algorithm Identifier Encryption Padding (OAEP) . . . . . . . . . . . . . . . . 11
Cross-Reference . . . . . . . . . . . . . . . . . . . 13 4.6. Key Agreement with Elliptic Curve Diffie-Hellman
Appendix B. Encryption Algorithm Identifier Cross-Reference . . . 15 Ephemeral Static (ECDH-ES) . . . . . . . . . . . . . . . . 12
Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 19 4.7. Key Encryption with AES Key Wrap . . . . . . . . . . . . . 12
Appendix D. Document History . . . . . . . . . . . . . . . . . . 19 4.8. Plaintext Encryption with AES Cipher Block Chaining
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 19 (CBC) Mode . . . . . . . . . . . . . . . . . . . . . . . . 12
4.9. Plaintext Encryption with AES Galois/Counter Mode (GCM) . 12
4.10. Integrity Calculation with HMAC SHA-256, HMAC SHA-384,
or HMAC SHA-512 . . . . . . . . . . . . . . . . . . . . . 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
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
Appendix A. Digital Signature/MAC Algorithm Identifier
Cross-Reference . . . . . . . . . . . . . . . . . . . 19
Appendix B. Encryption Algorithm Identifier Cross-Reference . . . 21
Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . . 25
Appendix D. Document History . . . . . . . . . . . . . . . . . . 25
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 26
1. Introduction 1. Introduction
The JSON Web Algorithms (JWA) specification enumerates cryptographic The JSON Web Algorithms (JWA) specification enumerates cryptographic
algorithms and identifiers to be used with the JSON Web Signature algorithms and identifiers to be used with the JSON Web Signature
(JWS) [JWS] and JSON Web Encryption (JWE) [JWE] specifications. (JWS) [JWS] and JSON Web Encryption (JWE) [JWE] specifications.
Enumerating the algorithms and identifiers for them in this Enumerating the algorithms and identifiers for them in this
specification, rather than in the JWS and JWE specifications, is specification, rather than in the JWS and JWE specifications, is
intended to allow them to remain unchanged in the face of changes in intended to allow them to remain unchanged in the face of changes in
the set of required, recommended, optional, and deprecated algorithms the set of required, recommended, optional, and deprecated algorithms
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families. families.
2. Terminology 2. Terminology
This specification uses the terminology defined by the JSON Web This specification uses the terminology defined by the JSON Web
Signature (JWS) [JWS] and JSON Web Encryption (JWE) [JWE] Signature (JWS) [JWS] and JSON Web Encryption (JWE) [JWE]
specifications. specifications.
3. Cryptographic Algorithms for JWS 3. Cryptographic Algorithms for JWS
JWS uses cryptographic algorithms to sign the contents of the JWS JWS uses cryptographic algorithms to digitally sign or MAC the
Header and the JWS Payload. The use of the following algorithms for contents of the JWS Header and the JWS Payload. The use of the
producing JWSs is defined in this section. following algorithms for producing JWSs is defined in this section.
The table below Table 1 is the set of "alg" (algorithm) header 3.1. "alg" (Algorithm) Header Parameter Values for JWS
parameter values defined by this specification for use with JWS, each
of which is explained in more detail in the following sections: 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 | Algorithm | | alg Parameter | Digital Signature or MAC Algorithm |
| Value | | | Value | |
+--------------------+----------------------------------------------+ +--------------------+----------------------------------------------+
| HS256 | HMAC using SHA-256 hash algorithm | | HS256 | HMAC using SHA-256 hash algorithm |
| HS384 | HMAC using SHA-384 hash algorithm | | HS384 | HMAC using SHA-384 hash algorithm |
| HS512 | HMAC using SHA-512 hash algorithm | | HS512 | HMAC using SHA-512 hash algorithm |
| RS256 | RSA using SHA-256 hash algorithm | | RS256 | RSA using SHA-256 hash algorithm |
| RS384 | RSA using SHA-384 hash algorithm | | RS384 | RSA using SHA-384 hash algorithm |
| RS512 | RSA using SHA-512 hash algorithm | | RS512 | RSA using SHA-512 hash algorithm |
| ES256 | ECDSA using P-256 curve and SHA-256 hash | | ES256 | ECDSA using P-256 curve and SHA-256 hash |
| | algorithm | | | algorithm |
| ES384 | ECDSA using P-384 curve and SHA-384 hash | | ES384 | ECDSA using P-384 curve and SHA-384 hash |
| | algorithm | | | algorithm |
| ES512 | ECDSA using P-521 curve and SHA-512 hash | | ES512 | ECDSA using P-521 curve and SHA-512 hash |
| | algorithm | | | algorithm |
| none | No digital signature or HMAC value included | | none | No digital signature or MAC value included |
+--------------------+----------------------------------------------+ +--------------------+----------------------------------------------+
Table 1: JWS Defined "alg" Parameter Values
See Appendix A for a table cross-referencing the digital signature See Appendix A for a table cross-referencing the digital signature
and HMAC "alg" (algorithm) values used in this specification with the and MAC "alg" (algorithm) values used in this specification with the
equivalent identifiers used by other standards and software packages. equivalent identifiers used by other standards and software packages.
Of these algorithms, only HMAC SHA-256 and "none" MUST be implemented Of these algorithms, only HMAC SHA-256 and "none" MUST be implemented
by conforming JWS implementations. It is RECOMMENDED that by conforming JWS implementations. It is RECOMMENDED that
implementations also support the RSA SHA-256 and ECDSA P-256 SHA-256 implementations also support the RSA SHA-256 and ECDSA P-256 SHA-256
algorithms. Support for other algorithms and key sizes is OPTIONAL. algorithms. Support for other algorithms and key sizes is OPTIONAL.
3.1. Creating a JWS with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 3.2. MAC with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512
Hash based Message Authentication Codes (HMACs) enable one to use a Hash-based Message Authentication Codes (HMACs) enable one to use a
secret plus a cryptographic hash function to generate a Message secret plus a cryptographic hash function to generate a Message
Authentication Code (MAC). This can be used to demonstrate that the Authentication Code (MAC). This can be used to demonstrate that the
MAC matches the hashed content, in this case the JWS Secured Input, MAC matches the hashed content, in this case the JWS Secured Input,
which therefore demonstrates that whoever generated the MAC was in which therefore demonstrates that whoever generated the MAC was in
possession of the secret. The means of exchanging the shared key is possession of the secret. The means of exchanging the shared key is
outside the scope of this specification. outside the scope of this specification.
The algorithm for implementing and validating HMACs is provided in The algorithm for implementing and validating HMACs is provided in
RFC 2104 [RFC2104]. This section defines the use of the HMAC SHA- RFC 2104 [RFC2104]. This section defines the use of the HMAC SHA-
256, HMAC SHA-384, and HMAC SHA-512 cryptographic hash functions as 256, HMAC SHA-384, and HMAC SHA-512 cryptographic hash functions as
defined in FIPS 180-3 [FIPS.180-3]. The "alg" (algorithm) header defined in FIPS 180-3 [FIPS.180-3]. The "alg" (algorithm) header
parameter values "HS256", "HS384", and "HS512" are used in the JWS parameter values "HS256", "HS384", and "HS512" are used in the JWS
Header to indicate that the Encoded JWS Signature contains a Header to indicate that the Encoded JWS Signature contains a
base64url encoded HMAC value using the respective hash function. 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 SHA-256 MAC is generated as follows: The HMAC SHA-256 MAC is generated as follows:
1. Apply the HMAC SHA-256 algorithm to the UTF-8 representation of 1. Apply the HMAC SHA-256 algorithm to the bytes of the UTF-8
the JWS Secured Input using the shared key to produce an HMAC representation of the JWS Secured Input (which is the same as the
ASCII representation) using the shared key to produce an HMAC
value. value.
2. Base64url encode the resulting HMAC value. 2. Base64url encode the resulting HMAC value.
The output is the Encoded JWS Signature for that JWS. The output is the Encoded JWS Signature for that JWS.
The HMAC SHA-256 MAC for a JWS is validated as follows: The HMAC SHA-256 MAC for a JWS is validated as follows:
1. Apply the HMAC SHA-256 algorithm to the UTF-8 representation of 1. Apply the HMAC SHA-256 algorithm to the bytes of the UTF-8
the JWS Secured Input of the JWS using the shared key. 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. 2. Base64url encode the resulting HMAC value.
3. If the Encoded JWS Signature and the base64url encoded 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 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 used to generate the HMAC on the JWS and that the contents of the
JWS have not be tampered with. JWS have not be tampered with.
4. If the validation fails, the JWS MUST be rejected. 4. If the validation fails, the JWS MUST be rejected.
Alternatively, the Encoded JWS Signature MAY be base64url decoded to Alternatively, the Encoded JWS Signature MAY be base64url decoded to
produce the JWS Signature and this value can be compared with the produce the JWS Signature and this value can be compared with the
computed HMAC value, as this comparison produces the same result as computed HMAC value, as this comparison produces the same result as
comparing the encoded values. comparing the encoded values.
Securing content with the HMAC SHA-384 and HMAC SHA-512 algorithms is Securing content with the HMAC SHA-384 and HMAC SHA-512 algorithms is
performed identically to the procedure for HMAC SHA-256 - just with performed identically to the procedure for HMAC SHA-256 - just with
correspondingly longer minimum key sizes and result values. correspondingly larger minimum key sizes and result values.
3.2. Creating a JWS with RSA SHA-256, RSA SHA-384, or RSA SHA-512 3.3. Digital Signature with RSA SHA-256, RSA SHA-384, or RSA SHA-512
This section defines the use of the RSASSA-PKCS1-v1_5 digital This section defines the use of the RSASSA-PKCS1-v1_5 digital
signature algorithm as defined in RFC 3447 [RFC3447], Section 8.2 signature algorithm as defined in RFC 3447 [RFC3447], Section 8.2
(commonly known as PKCS#1), using SHA-256, SHA-384, or SHA-512 as the (commonly known as PKCS#1), using SHA-256, SHA-384, or SHA-512 as the
hash function. The RSASSA-PKCS1-v1_5 algorithm is described in FIPS hash function. The RSASSA-PKCS1-v1_5 algorithm is described in FIPS
186-3 [FIPS.186-3], Section 5.5, and the SHA-256, SHA-384, and SHA- 186-3 [FIPS.186-3], Section 5.5, and the SHA-256, SHA-384, and SHA-
512 cryptographic hash functions are defined in FIPS 180-3 512 cryptographic hash functions are defined in FIPS 180-3
[FIPS.180-3]. The "alg" (algorithm) header parameter values "RS256", [FIPS.180-3]. The "alg" (algorithm) header parameter values "RS256",
"RS384", and "RS512" are used in the JWS Header to indicate that the "RS384", and "RS512" are used in the JWS Header to indicate that the
Encoded JWS Signature contains a base64url encoded RSA digital Encoded JWS Signature contains a base64url encoded RSA digital
signature using the respective hash function. signature using the respective hash function.
A 2048-bit or longer key length MUST be used with this algorithm. 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 RSASSA-PKCS1 for new applications and instead
requests that people transition to RSASSA-PSS, for interoperability
reasons, this specification does use RSASSA-PKCS1 because it commonly
implemented.
The RSA SHA-256 digital signature is generated as follows: The RSA SHA-256 digital signature is generated as follows:
1. Generate a digital signature of the UTF-8 representation of the 1. Generate a digital signature of the bytes of the UTF-8
JWS Secured Input using RSASSA-PKCS1-V1_5-SIGN and the SHA-256 representation of the JWS Secured Input (which is the same as the
hash function with the desired private key. The output will be a ASCII representation) using RSASSA-PKCS1-V1_5-SIGN and the SHA-
byte array. 256 hash function with the desired private key. The output will
be a byte array.
2. Base64url encode the resulting byte array. 2. Base64url encode the resulting byte array.
The output is the Encoded JWS Signature for that JWS. The output is the Encoded JWS Signature for that JWS.
The RSA SHA-256 digital signature for a JWS is validated as follows: The RSA SHA-256 digital signature for a JWS is validated as follows:
1. Take the Encoded JWS Signature and base64url decode it into a 1. Take the Encoded JWS Signature and base64url decode it into a
byte array. If decoding fails, the JWS MUST be rejected. byte array. If decoding fails, the JWS MUST be rejected.
2. Submit the UTF-8 representation of the JWS Secured Input and the 2. Submit the bytes of the UTF-8 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 public key corresponding to the private key used by the signer to
the RSASSA-PKCS1-V1_5-VERIFY algorithm using SHA-256 as the hash the RSASSA-PKCS1-V1_5-VERIFY algorithm using SHA-256 as the hash
function. function.
3. If the validation fails, the JWS MUST be rejected. 3. If the validation fails, the JWS MUST be rejected.
Signing with the RSA SHA-384 and RSA SHA-512 algorithms is performed Signing with the RSA SHA-384 and RSA SHA-512 algorithms is performed
identically to the procedure for RSA SHA-256 - just with identically to the procedure for RSA SHA-256 - just with
correspondingly longer minimum key sizes and result values. correspondingly larger result values.
3.3. Creating a JWS with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or 3.4. Digital Signature with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384,
ECDSA P-521 SHA-512 or ECDSA P-521 SHA-512
The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined by The Elliptic Curve Digital Signature Algorithm (ECDSA) is defined by
FIPS 186-3 [FIPS.186-3]. ECDSA provides for the use of Elliptic FIPS 186-3 [FIPS.186-3]. ECDSA provides for the use of Elliptic
Curve cryptography, which is able to provide equivalent security to Curve cryptography, which is able to provide equivalent security to
RSA cryptography but using shorter key lengths and with greater RSA cryptography but using shorter key sizes and with greater
processing speed. This means that ECDSA digital signatures will be processing speed. This means that ECDSA digital signatures will be
substantially smaller in terms of length than equivalently strong RSA substantially smaller in terms of length than equivalently strong RSA
digital signatures. digital signatures.
This specification defines the use of ECDSA with the P-256 curve and This specification defines the use of ECDSA with the P-256 curve and
the SHA-256 cryptographic hash function, ECDSA with the P-384 curve the SHA-256 cryptographic hash function, ECDSA with the P-384 curve
and the SHA-384 hash function, and ECDSA with the P-521 curve and the and the SHA-384 hash function, and ECDSA with the P-521 curve and the
SHA-512 hash function. The P-256, P-384, and P-521 curves are also SHA-512 hash function. The P-256, P-384, and P-521 curves are also
defined in FIPS 186-3. The "alg" (algorithm) header parameter values defined in FIPS 186-3. The "alg" (algorithm) header parameter values
"ES256", "ES384", and "ES512" are used in the JWS Header to indicate "ES256", "ES384", and "ES512" are used in the JWS Header to indicate
that the Encoded JWS Signature contains a base64url encoded ECDSA that the Encoded JWS Signature contains a base64url encoded ECDSA
P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512 digital P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512 digital
signature, respectively. signature, respectively.
A key of size 160 bits or larger MUST be used with these algorithms.
The ECDSA P-256 SHA-256 digital signature is generated as follows: The ECDSA P-256 SHA-256 digital signature is generated as follows:
1. Generate a digital signature of the UTF-8 representation of the 1. Generate a digital signature of the bytes of the UTF-8
JWS Secured Input using ECDSA P-256 SHA-256 with the desired representation of the JWS Secured Input (which is the same as the
ASCII representation) using ECDSA P-256 SHA-256 with the desired
private key. The output will be the EC point (R, S), where R and private key. The output will be the EC point (R, S), where R and
S are unsigned integers. S are unsigned integers.
2. Turn R and S into byte arrays in big endian order. Each array 2. Turn R and S into byte arrays in big endian order. Each array
will be 32 bytes long. will 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.
4. Base64url encode the resulting 64 byte array. 4. Base64url encode the resulting 64 byte array.
skipping to change at page 7, line 14 skipping to change at page 8, line 29
The ECDSA P-256 SHA-256 digital signature for a JWS is validated as The ECDSA P-256 SHA-256 digital signature for a JWS is validated as
follows: follows:
1. Take the Encoded JWS Signature and base64url decode it into a 1. Take the Encoded JWS Signature and base64url decode it into a
byte array. If decoding fails, the JWS MUST be rejected. 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.
3. Split the 64 byte array into two 32 byte arrays. The first array 3. Split the 64 byte array into two 32 byte arrays. The first array
will be R and the second S. Remember that the byte arrays are in will be R and the second S (with both being in big endian byte
big endian byte order; please check the ECDSA validator in use to order).
see what byte order it requires.
4. Submit the UTF-8 representation of the JWS Secured Input, R, S 4. Submit the bytes of the UTF-8 representation of the JWS Secured
and the public key (x, y) to the ECDSA P-256 SHA-256 validator. Input (which is the same as the ASCII representation), R, S and
the public key (x, y) to the ECDSA P-256 SHA-256 validator.
5. If the validation fails, the JWS MUST be rejected. 5. If the validation fails, the JWS MUST be rejected.
The ECDSA validator will then determine if the digital signature is The ECDSA validator will then determine if the digital signature is
valid, given the inputs. Note that ECDSA digital signature contains valid, given the inputs. Note that ECDSA digital signature contains
a value referred to as K, which is a random number generated for each a value referred to as K, which is a random number generated for each
digital signature instance. This means that two ECDSA digital digital signature instance. This means that two ECDSA digital
signatures using exactly the same input parameters will output signatures using exactly the same input parameters will output
different signature values because their K values will be different. different signature values because their K values will be different.
The consequence of this is that one must validate an ECDSA digital The consequence of this is that one must validate an ECDSA digital
signature by submitting the previously specified inputs to an ECDSA signature by submitting the previously specified inputs to an ECDSA
validator. validator.
Signing with the ECDSA P-384 SHA-384 and ECDSA P-521 SHA-512 Signing with the ECDSA P-384 SHA-384 and ECDSA P-521 SHA-512
algorithms is performed identically to the procedure for ECDSA P-256 algorithms is performed identically to the procedure for ECDSA P-256
SHA-256 - just with correspondingly longer minimum key sizes and SHA-256 - just with correspondingly larger result values.
result values.
3.4. Creating a Plaintext JWS 3.5. Creating a Plaintext JWS
To support use cases where the content is secured by a means other To support use cases where the content is secured by a means other
than a digital signature or HMAC value, JWSs MAY also be created than a digital signature or MAC value, JWSs MAY also be created
without them. These are called "Plaintext JWSs". Plaintext JWSs without them. These are called "Plaintext JWSs". Plaintext JWSs
MUST use the "alg" value "none", and are formatted identically to MUST use the "alg" value "none", and are formatted identically to
other JWSs, but with an empty JWS Signature value. other JWSs, but with an empty JWS Signature value.
3.5. Additional Digital Signature/HMAC Algorithms 3.6. Additional Digital Signature/MAC Algorithms and Parameters
Additional algorithms MAY be used to protect JWSs with corresponding Additional algorithms MAY be used to protect JWSs with corresponding
"alg" (algorithm) header parameter values being defined to refer to "alg" (algorithm) header parameter values being defined to refer to
them. New "alg" header parameter values SHOULD either be defined in them. New "alg" header parameter values SHOULD either be defined in
the IANA JSON Web Signature Algorithms registry or be a URI that the IANA JSON Web Signature and Encryption Algorithms registry
contains a collision resistant namespace. In particular, it is Section 6.2 or be a URI that contains a collision resistant
permissible to use the algorithm identifiers defined in XML DSIG namespace. In particular, it is permissible to use the algorithm
[RFC3275] and related specifications as "alg" values. identifiers defined in XML DSIG [RFC3275], XML DSIG 2.0
[W3C.CR-xmldsig-core2-20120124], 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
specifications.
4. Cryptographic Algorithms for JWE 4. Cryptographic Algorithms for JWE
JWE uses cryptographic algorithms to encrypt the Content Encryption JWE uses cryptographic algorithms to encrypt the Content Master Key
Key (CEK) and the Plaintext. This section specifies a set of (CMK) and the Plaintext. This section specifies a set of specific
specific algorithms for these purposes. algorithms for these purposes.
The table below Table 2 is the set of "alg" (algorithm) header 4.1. "alg" (Algorithm) Header Parameter Values for JWE
parameter values that are defined by this specification for use with
JWE. These algorithms are used to encrypt the CEK, which produces The table below is the set of "alg" (algorithm) header parameter
the JWE Encrypted Key. 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 | Encryption Algorithm | | alg | Key Encryption or Agreement Algorithm |
| Parameter | | | Parameter | |
| Value | | | Value | |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| RSA1_5 | RSA using RSA-PKCS1-1.5 padding, as defined in RFC | | RSA1_5 | RSA using RSA-PKCS1-1.5 padding, as defined in RFC |
| | 3447 [RFC3447] | | | 3447 [RFC3447] |
| RSA-OAEP | RSA using Optimal Asymmetric Encryption Padding | | RSA-OAEP | RSA using Optimal Asymmetric Encryption Padding |
| | (OAEP), as defined in RFC 3447 [RFC3447] | | | (OAEP), as defined in RFC 3447 [RFC3447] |
| ECDH-ES | Elliptic Curve Diffie-Hellman Ephemeral Static, as | | ECDH-ES | Elliptic Curve Diffie-Hellman Ephemeral Static, as |
| | defined in RFC 6090 [RFC6090], and using the Concat | | | defined in RFC 6090 [RFC6090], and using the Concat |
| | KDF, as defined in [NIST-800-56A], where the Digest | | | KDF, as defined in Section 5.8.1 of [NIST.800-56A], |
| | Method is SHA-256 and all OtherInfo parameters are | | | where the Digest Method is SHA-256 and all OtherInfo |
| | the empty bit string | | | parameters are the empty bit string |
| A128KW | Advanced Encryption Standard (AES) Key Wrap Algorithm | | A128KW | Advanced Encryption Standard (AES) Key Wrap Algorithm |
| | using 128 bit keys, as defined in RFC 3394 [RFC3394] | | | using 128 bit keys, as defined in RFC 3394 [RFC3394] |
| A256KW | Advanced Encryption Standard (AES) Key Wrap Algorithm | | A256KW | Advanced Encryption Standard (AES) Key Wrap Algorithm |
| | using 256 bit keys, as defined in RFC 3394 [RFC3394] | | | using 256 bit keys, as defined in RFC 3394 [RFC3394] |
| A512KW | Advanced Encryption Standard (AES) Key Wrap Algorithm |
| | using 512 bit keys, as defined in RFC 3394 [RFC3394] |
| A128GCM | Advanced Encryption Standard (AES) using 128 bit keys |
| | in Galois/Counter Mode, as defined in [FIPS-197] and |
| | [NIST-800-38D] |
| A256GCM | Advanced Encryption Standard (AES) using 256 bit keys |
| | in Galois/Counter Mode, as defined in [FIPS-197] and |
| | [NIST-800-38D] |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
Table 2: JWE Defined "alg" Parameter Values 4.2. "enc" (Encryption Method) Header Parameter Values for JWE
The table below Table 3 is the set of "enc" (encryption method) The table below is the set of "enc" (encryption method) header
header parameter values that are defined by this specification for parameter values that are defined by this specification for use with
use with JWE. These algorithms are used to encrypt the Plaintext, JWE. These algorithms are used to encrypt the Plaintext, which
which produces the Ciphertext. produces the Ciphertext.
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| enc | Symmetric Encryption Algorithm | | enc | Block Encryption Algorithm |
| Parameter | | | Parameter | |
| Value | | | Value | |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| A128CBC | Advanced Encryption Standard (AES) using 128 bit keys | | A128CBC | Advanced Encryption Standard (AES) using 128 bit keys |
| | in Cipher Block Chaining mode, as defined in | | | in Cipher Block Chaining (CBC) mode using PKCS #5 |
| | [FIPS-197] and [NIST-800-38A] | | | padding, as defined in [FIPS.197] and [NIST.800-38A] |
| A256CBC | Advanced Encryption Standard (AES) using 256 bit keys | | A256CBC | Advanced Encryption Standard (AES) using 256 bit keys |
| | in Cipher Block Chaining mode, as defined in | | | in Cipher Block Chaining (CBC) mode using PKCS #5 |
| | [FIPS-197] and [NIST-800-38A] | | | padding, as defined in [FIPS.197] and [NIST.800-38A] |
| A128GCM | Advanced Encryption Standard (AES) using 128 bit keys | | A128GCM | Advanced Encryption Standard (AES) using 128 bit keys |
| | in Galois/Counter Mode, as defined in [FIPS-197] and | | | in Galois/Counter Mode (GCM), as defined in |
| | [NIST-800-38D] | | | [FIPS.197] and [NIST.800-38D] |
| A256GCM | Advanced Encryption Standard (AES) using 256 bit keys | | A256GCM | Advanced Encryption Standard (AES) using 256 bit keys |
| | in Galois/Counter Mode, as defined in [FIPS-197] and | | | in Galois/Counter Mode (GCM), as defined in |
| | [NIST-800-38D] | | | [FIPS.197] and [NIST.800-38D] |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
Table 3: JWE Defined "enc" Parameter Values
See Appendix B for a table cross-referencing the encryption "alg" See Appendix B for a table cross-referencing the encryption "alg"
(algorithm) and "enc" (encryption method) values used in this (algorithm) and "enc" (encryption method) values used in this
specification with the equivalent identifiers used by other standards specification with the equivalent identifiers used by other standards
and software packages. and software packages.
Of these algorithms, only RSA-PKCS1-1.5 with 2048 bit keys, AES-128- Of these "alg" and "enc" algorithms, only RSA-PKCS1-1.5 with 2048 bit
CBC, and AES-256-CBC MUST be implemented by conforming JWE keys, AES-128-KW, AES-256-KW, AES-128-CBC, and AES-256-CBC MUST be
implementations. It is RECOMMENDED that implementations also support implemented by conforming JWE implementations. It is RECOMMENDED
ECDH-ES with 256 bit keys, AES-128-GCM, and AES-256-GCM. Support for that implementations also support ECDH-ES with 256 bit keys, AES-128-
other algorithms and key sizes is OPTIONAL. GCM, and AES-256-GCM. Support for other algorithms and key sizes is
OPTIONAL.
4.1. Encrypting a JWE with TBD 4.3. "int" (Integrity Algorithm) Header Parameter Values for JWE
TBD: Descriptions of the particulars of using each specified The table below is the set of "int" (integrity algorithm) header
encryption algorithm go here. 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. />
4.2. Additional Encryption Algorithms +---------------------+-----------------------------------+
| int Parameter Value | Algorithm |
+---------------------+-----------------------------------+
| HS256 | HMAC using SHA-256 hash algorithm |
| HS384 | HMAC using SHA-384 hash algorithm |
| HS512 | HMAC using SHA-512 hash algorithm |
+---------------------+-----------------------------------+
Of these "int" algorithms, only HMAC SHA-256 MUST be implemented by
conforming JWE implementations. It is RECOMMENDED that
implementations also support the RSA SHA-256 and ECDSA P-256 SHA-256
algorithms.
4.4. Key Encryption with RSA using RSA-PKCS1-1.5 Padding
This section defines the specifics of encrypting a JWE CMK with RSA
using RSA-PKCS1-1.5 padding, as defined in RFC 3447 [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)
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 "RSA-OAEP" 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 Diffie-Hellman Ephemeral Static
(ECDH-ES)
This section defines the specifics of agreeing upon a JWE CMK with
Elliptic Curve Diffie-Hellman Ephemeral Static, as defined in RFC
6090 [RFC6090], and using the Concat KDF, as defined in Section 5.8.1
of [NIST.800-56A], where the Digest Method is SHA-256 and all
OtherInfo parameters are the empty bit string. The "alg" header
parameter value "ECDH-ES" 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.
An "epk" (ephemeral public key) value MUST only be used for a single
key agreement transaction.
4.7. 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.
4.8. Plaintext Encryption with AES Cipher Block Chaining (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.800-38A]. 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.
4.9. Plaintext Encryption with AES Galois/Counter Mode (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.800-38D]. 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.
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 requested size of the "authentication tag" output MUST be the
same as the key size (for instance, 128 bits for "A128GCM").
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 SHA-256, HMAC SHA-384, or HMAC
SHA-512
This section defines the specifics of computing a JWE Integrity Value
with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 as defined in FIPS
180-3 [FIPS.180-3]. The "int" header parameter values "HS256",
"HS384", or "HS512" are used in this case.
A key of the same size as the hash output (for instance, 256 bits for
"HS256") or larger MUST be used with this algorithm.
4.11. Additional Encryption Algorithms and Parameters
Additional algorithms MAY be used to protect JWEs with corresponding Additional algorithms MAY be used to protect JWEs with corresponding
"alg" (algorithm) and "enc" (encryption method) header parameter "alg" (algorithm), "enc" (encryption method), and "int" (integrity
values being defined to refer to them. New "alg" and "enc" header algorithm) header parameter values being defined to refer to them.
parameter values SHOULD either be defined in the IANA JSON Web New "alg", "enc", and "int" header parameter values SHOULD either be
Encryption Algorithms registry or be a URI that contains a collision defined in the IANA JSON Web Signature and Encryption Algorithms
resistant namespace. In particular, it is permissible to use the registry Section 6.2 or be a URI that contains a collision resistant
algorithm identifiers defined in XML Encryption namespace. In particular, it is permissible to use the algorithm
identifiers defined in XML Encryption [W3C.REC-xmlenc-core-20021210],
XML Encryption 1.1 [W3C.CR-xmlenc-core1-20120313], and related
specifications as "alg", "enc", and "int" values.
[W3C.REC-xmlenc-core-20021210], XML Encryption 1.1 As indicated by the common registry, JWSs and JWEs share a common
[W3C.CR-xmlenc-core1-20110303], and related specifications as "alg" "alg" value space. The values used by the two specifications MUST be
and "enc" values. distinct, as the "alg" value MAY be used to determine whether the
object is a JWS or JWE.
5. IANA Considerations 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
specifications.
This specification calls for: 5. Cryptographic Algorithms for JWK
o A new IANA registry entitled "JSON Web Signature Algorithms" for A JSON Web Key (JWK) [JWK] is a JSON data structure that represents a
values of the JWS "alg" (algorithm) header parameter is defined in public key. A JSON Web Key Set (JWK Set) is a JSON data structure
Section 3.5. Inclusion in the registry is RFC Required in the RFC for representing a set of JWKs. This section specifies a set of
5226 [RFC5226] sense. The registry will just record the "alg" algorithm families to be used for those public keys and the algorithm
value and a pointer to the RFC that defines it. This family specific parameters for representing those keys.
specification defines inclusion of the algorithm values defined in
Table 1.
o A new IANA registry entitled "JSON Web Encryption Algorithms" for 5.1. "alg" (Algorithm Family) Parameter Values for JWK
values used with the JWE "alg" (algorithm) and "enc" (encryption
method) header parameters is defined in Section 4.2. Inclusion in
the registry is RFC Required in the RFC 5226 [RFC5226] sense. The
registry will record the "alg" or "enc" value and a pointer to the
RFC that defines it. This specification defines inclusion of the
algorithm values defined in Table 2 and Table 3.
6. Security Considerations The table below is the set of "alg" (algorithm family) parameter
values that are defined by this specification for use in JWKs.
TBD +---------------------+----------------------------------------+
| alg Parameter Value | Algorithm Family |
+---------------------+----------------------------------------+
| EC | Elliptic Curve [FIPS.186-3] key family |
| RSA | RSA [RFC3447] key family |
+---------------------+----------------------------------------+
7. Open Issues and Things To Be Done (TBD) 5.2. JWK Parameters for Elliptic Curve Keys
The following items remain to be done in this draft: JWKs can represent Elliptic Curve [FIPS.186-3] keys. In this case,
the "alg" member value MUST be "EC". Furthermore, these additional
members MUST be present:
o Specify minimum required key sizes for all algorithms. 5.2.1. "crv" (Curve) Parameter
o Specify which algorithms require Initialization Vectors (IVs) and The "crv" (curve) member identifies the cryptographic curve used with
minimum required lengths for those IVs. the key. Values defined by this specification are "P-256", "P-384"
and "P-521". 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.
o Since RFC 3447 Section 8 explicitly calls for people NOT to adopt 5.2.2. "x" (X Coordinate) Parameter
RSASSA-PKCS1 for new applications and instead requests that people
transition to RSASSA-PSS, we probably need some Security
Considerations text explaining why RSASSA-PKCS1 is being used
(it's what's commonly implemented) and what the potential
consequences are.
o Should we define the use of RFC 5649 key wrapping functions, which The "x" (x coordinate) member contains the x coordinate for the
allow arbitrary key sizes, in addition to the current use of RFC elliptic curve point. It is represented as the base64url encoding of
3394 key wrapping functions, which require that keys be multiples the coordinate's big endian representation.
of 64 bits? Is this needed in practice?
o Decide whether to move the JWK algorithm family definitions "EC" 5.2.3. "y" (Y Coordinate) Parameter
and "RSA" here. This would likely result in all the family-
specific parameter definitions also moving here ("crv", "x", "y",
"mod", "exp"), leaving very little normative text in the JWK spec
itself. This seems like it would reduce spec readability and so
was not done.
o It would be good to say somewhere, in normative language, that The "y" (y coordinate) member contains the y coordinate for the
eventually the algorithms and/or key sizes currently specified elliptic curve point. It is represented as the base64url encoding of
will no longer be considered sufficiently secure and will be the coordinate's big endian representation.
removed. Therefore, implementers MUST be prepared for this
eventuality.
o Write the Security Considerations section. 5.3. JWK Parameters for RSA Keys
8. References JWKs can represent RSA [RFC3447] keys. In this case, the "alg"
member value MUST be "RSA". Furthermore, these additional members
MUST be present:
8.1. Normative References 5.3.1. "mod" (Modulus) Parameter
[FIPS-197] The "mod" (modulus) member contains the modulus value for the RSA
National Institute of Standards and Technology (NIST), public key. It is represented as the base64url encoding of the
"Advanced Encryption Standard (AES)", FIPS PUB 197, value's big endian representation.
November 2001.
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.
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.
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.
6. IANA Considerations
6.1. JSON Web Signature and Encryption Header Parameters Registry
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.
6.2. 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.
6.3. JSON Web Signature and Encryption "typ" Values Registry
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.
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.
6.4. JSON Web Key Parameters Registry
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.
6.5. 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.
7. Security Considerations
The security considerations in the JWS, JWE, and JWK specifications
also 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)
The following items remain to be done in this draft:
o Find values for encryption algorithm cross-reference table
currently listed as "TBD" or determine that they do not exist.
9. References
9.1. Normative References
[FIPS.180-3] [FIPS.180-3]
National Institute of Standards and Technology, "Secure National Institute of Standards and Technology, "Secure
Hash Standard (SHS)", FIPS PUB 180-3, October 2008. Hash Standard (SHS)", FIPS PUB 180-3, October 2008.
[FIPS.186-3] [FIPS.186-3]
National Institute of Standards and Technology, "Digital National Institute of Standards and Technology, "Digital
Signature Standard (DSS)", FIPS PUB 186-3, June 2009. Signature Standard (DSS)", FIPS PUB 186-3, June 2009.
[FIPS.197]
National Institute of Standards and Technology (NIST),
"Advanced Encryption Standard (AES)", FIPS PUB 197,
November 2001.
[JWE] Jones, M., Rescorla, E., and J. Hildebrand, "JSON Web [JWE] Jones, M., Rescorla, E., and J. Hildebrand, "JSON Web
Encryption (JWE)", March 2012. Encryption (JWE)", May 2012.
[JWK] Jones, M., "JSON Web Key (JWK)", May 2012.
[JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web [JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", March 2012. Signature (JWS)", May 2012.
[NIST-800-38A] [NIST.800-38A]
National Institute of Standards and Technology (NIST), National Institute of Standards and Technology (NIST),
"Recommendation for Block Cipher Modes of Operation", "Recommendation for Block Cipher Modes of Operation",
NIST PUB 800-38A, December 2001. NIST PUB 800-38A, December 2001.
[NIST-800-38D] [NIST.800-38D]
National Institute of Standards and Technology (NIST), National Institute of Standards and Technology (NIST),
"Recommendation for Block Cipher Modes of Operation: "Recommendation for Block Cipher Modes of Operation:
Galois/Counter Mode (GCM) and GMAC", NIST PUB 800-38D, Galois/Counter Mode (GCM) and GMAC", NIST PUB 800-38D,
December 2001. December 2001.
[NIST-800-56A] [NIST.800-56A]
National Institute of Standards and Technology (NIST), National Institute of Standards and Technology (NIST),
"Recommendation for Pair-Wise Key Establishment Schemes "Recommendation for Pair-Wise Key Establishment Schemes
Using Discrete Logarithm Cryptography (Revised)", NIST PUB Using Discrete Logarithm Cryptography (Revised)", NIST PUB
800-56A, March 2007. 800-56A, 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- [RFC2104] Krawczyk, H., Bellare, M., and R. Canetti, "HMAC: Keyed-
Hashing for Message Authentication", RFC 2104, Hashing for Message Authentication", RFC 2104,
February 1997. February 1997.
[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, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC3394] Schaad, J. and R. Housley, "Advanced Encryption Standard [RFC3394] Schaad, J. and R. Housley, "Advanced Encryption Standard
(AES) Key Wrap Algorithm", RFC 3394, September 2002. (AES) Key Wrap Algorithm", RFC 3394, September 2002.
skipping to change at page 12, line 38 skipping to change at page 18, line 31
Standards (PKCS) #1: RSA Cryptography Specifications Standards (PKCS) #1: RSA Cryptography Specifications
Version 2.1", RFC 3447, February 2003. Version 2.1", RFC 3447, February 2003.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
[RFC6090] McGrew, D., Igoe, K., and M. Salter, "Fundamental Elliptic [RFC6090] McGrew, D., Igoe, K., and M. Salter, "Fundamental Elliptic
Curve Cryptography Algorithms", RFC 6090, February 2011. Curve Cryptography Algorithms", RFC 6090, February 2011.
8.2. Informative References 9.2. Informative References
[CanvasApp] [CanvasApp]
Facebook, "Canvas Applications", 2010. Facebook, "Canvas Applications", 2010.
[I-D.rescorla-jsms] [I-D.rescorla-jsms]
Rescorla, E. and J. Hildebrand, "JavaScript Message Rescorla, E. and J. Hildebrand, "JavaScript Message
Security Format", draft-rescorla-jsms-00 (work in Security Format", draft-rescorla-jsms-00 (work in
progress), March 2011. progress), March 2011.
[JCA] Oracle, "Java Cryptography Architecture", 2011. [JCA] Oracle, "Java Cryptography Architecture", 2011.
skipping to change at page 13, line 16 skipping to change at page 19, line 9
September 2010. September 2010.
[MagicSignatures] [MagicSignatures]
Panzer (editor), J., Laurie, B., and D. Balfanz, "Magic Panzer (editor), J., Laurie, B., and D. Balfanz, "Magic
Signatures", January 2011. Signatures", January 2011.
[RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible Markup [RFC3275] Eastlake, D., Reagle, J., and D. Solo, "(Extensible Markup
Language) XML-Signature Syntax and Processing", RFC 3275, Language) XML-Signature Syntax and Processing", RFC 3275,
March 2002. March 2002.
[W3C.CR-xmlenc-core1-20110303] [W3C.CR-xmldsig-core2-20120124]
Hirsch, F., Roessler, T., Reagle, J., and D. Eastlake, Eastlake, D., Reagle, J., Yiu, K., Solo, D., Datta, P.,
Hirsch, F., Cantor, S., and T. Roessler, "XML Signature
Syntax and Processing Version 2.0", World Wide Web
Consortium CR CR-xmldsig-core2-20120124, January 2012,
<http://www.w3.org/TR/2012/CR-xmldsig-core2-20120124>.
[W3C.CR-xmlenc-core1-20120313]
Eastlake, D., Reagle, J., Roessler, T., and F. Hirsch,
"XML Encryption Syntax and Processing Version 1.1", World "XML Encryption Syntax and Processing Version 1.1", World
Wide Web Consortium CR CR-xmlenc-core1-20110303, Wide Web Consortium CR CR-xmlenc-core1-20120313,
March 2011, March 2012,
<http://www.w3.org/TR/2011/CR-xmlenc-core1-20110303>. <http://www.w3.org/TR/2012/CR-xmlenc-core1-20120313>.
[W3C.REC-xmlenc-core-20021210] [W3C.REC-xmlenc-core-20021210]
Eastlake, D. and J. Reagle, "XML Encryption Syntax and Eastlake, D. and J. Reagle, "XML Encryption Syntax and
Processing", World Wide Web Consortium Recommendation REC- Processing", World Wide Web Consortium Recommendation REC-
xmlenc-core-20021210, December 2002, xmlenc-core-20021210, December 2002,
<http://www.w3.org/TR/2002/REC-xmlenc-core-20021210>. <http://www.w3.org/TR/2002/REC-xmlenc-core-20021210>.
Appendix A. Digital Signature/HMAC Algorithm Identifier Cross-Reference Appendix A. Digital Signature/MAC Algorithm Identifier Cross-Reference
This appendix contains a table cross-referencing the digital This appendix contains a table cross-referencing the digital
signature and HMAC "alg" (algorithm) values used in this signature and MAC "alg" (algorithm) values used in this specification
specification with the equivalent identifiers used by other standards with the equivalent identifiers used by other standards and software
and software packages. See XML DSIG [RFC3275] and Java Cryptography packages. See XML DSIG [RFC3275], XML DSIG 2.0
Architecture [JCA] for more information about the names defined by [W3C.CR-xmldsig-core2-20120124], and Java Cryptography Architecture
those documents. [JCA] for more information about the names defined by those
documents.
+-------+-----+----------------------------+----------+-------------+ +-------+-----+----------------------------+----------+-------------+
| Algor | JWS | XML DSIG | JCA | OID | | Algor | JWS | XML DSIG | JCA | OID |
| ithm | | | | | | ithm | | | | |
+-------+-----+----------------------------+----------+-------------+ +-------+-----+----------------------------+----------+-------------+
| HMAC | HS2 | http://www.w3.org/2001/04/ | HmacSHA2 | 1.2.840.113 | | HMAC | HS2 | http://www.w3.org/2001/04/ | HmacSHA2 | 1.2.840.113 |
| using | 56 | xmldsig-more#hmac-sha256 | 56 | 549.2.9 | | using | 56 | xmldsig-more#hmac-sha256 | 56 | 549.2.9 |
| SHA-2 | | | | | | SHA-2 | | | | |
| 56 | | | | | | 56 | | | | |
| hash | | | | | | hash | | | | |
skipping to change at page 15, line 36 skipping to change at page 21, line 26
| P-521 | | | | | | P-521 | | | | |
| curve | | | | | | curve | | | | |
| and | | | | | | and | | | | |
| SHA-5 | | | | | | SHA-5 | | | | |
| 12 | | | | | | 12 | | | | |
| hash | | | | | | hash | | | | |
| algo | | | | | | algo | | | | |
| rithm | | | | | | rithm | | | | |
+-------+-----+----------------------------+----------+-------------+ +-------+-----+----------------------------+----------+-------------+
Table 4: Digital Signature/HMAC Algorithm Identifier Cross-Reference
Appendix B. Encryption Algorithm Identifier Cross-Reference Appendix B. Encryption Algorithm Identifier Cross-Reference
This appendix contains a table cross-referencing the "alg" This appendix contains a table cross-referencing the "alg"
(algorithm) and "enc" (encryption method) values used in this (algorithm) and "enc" (encryption method) values used in this
specification with the equivalent identifiers used by other standards specification with the equivalent identifiers used by other standards
and software packages. See XML Encryption and software packages. See XML Encryption
[W3C.REC-xmlenc-core-20021210], XML Encryption 1.1 [W3C.REC-xmlenc-core-20021210], XML Encryption 1.1
[W3C.CR-xmlenc-core1-20110303], and Java Cryptography Architecture [W3C.CR-xmlenc-core1-20120313], and Java Cryptography Architecture
[JCA] for more information about the names defined by those [JCA] for more information about the names defined by those
documents. documents.
+---------+-------+---------------------------+---------------------+ +---------+-------+---------------------------+---------------------+
| Algorit | JWE | XML ENC | JCA | | Algorit | JWE | XML ENC | JCA |
| hm | | | | | hm | | | |
+---------+-------+---------------------------+---------------------+ +---------+-------+---------------------------+---------------------+
| RSA | RSA1_ | http://www.w3.org/2001/04 | RSA/ECB/PKCS1Paddin | | RSA | RSA1_ | http://www.w3.org/2001/04 | RSA/ECB/PKCS1Paddin |
| using | 5 | /xmlenc#rsa-1_5 | g | | using | 5 | /xmlenc#rsa-1_5 | g |
| RSA-PKC | | | | | RSA-PKC | | | |
skipping to change at page 17, line 20 skipping to change at page 23, line 20
| ) Key | | | | | ) Key | | | |
| Wrap | | | | | Wrap | | | |
| Algo | | | | | Algo | | | |
| rithm R | | | | | rithm R | | | |
| FC 339 | | | | | FC 339 | | | |
| 4 [RF | | | | | 4 [RF | | | |
| C3394] | | | | | C3394] | | | |
| using25 | | | | | using25 | | | |
| 6 bitke | | | | | 6 bitke | | | |
| ys | | | | | ys | | | |
| Advance | A512K | http://www.w3.org/2001/04 | TBD |
| d | W | /xmlenc#kw-aes512 | |
| Encryp | | | |
| tion | | | |
| Stand | | | |
| ard(AES | | | |
| ) Key | | | |
| Wrap | | | |
| Algo | | | |
| rithm R | | | |
| FC 339 | | | |
| 4 [RF | | | |
| C3394] | | | |
| using51 | | | |
| 2 bitke | | | |
| ys | | | |
| Advance | A128C | http://www.w3.org/2001/04 | AES/CBC/PKCS5Paddin | | Advance | A128C | http://www.w3.org/2001/04 | AES/CBC/PKCS5Paddin |
| d | BC | /xmlenc#aes128-cbc | g | | d | BC | /xmlenc#aes128-cbc | g |
| Encryp | | | | | Encryp | | | |
| tion | | | | | tion | | | |
| Stand | | | | | Stand | | | |
| ard(AES | | | | | ard(AES | | | |
| ) usin | | | | | ) usin | | | |
| g 128 | | | | | g 128 | | | |
| bitkeys | | | | | bitkeys | | | |
| inCiph | | | | | inCiph | | | |
| er Bloc | | | | | er Bloc | | | |
| k Chai | | | | | k Chai | | | |
| ningmod | | | | | ning(CB | | | |
| e | | | | | C) mod | | | |
| e usi | | | |
| ng PKC | | | |
| S #5pad | | | |
| ding | | | |
| Advance | A256C | http://www.w3.org/2001/04 | AES/CBC/PKCS5Paddin | | Advance | A256C | http://www.w3.org/2001/04 | AES/CBC/PKCS5Paddin |
| d | BC | /xmlenc#aes256-cbc | g | | d | BC | /xmlenc#aes256-cbc | g |
| Encryp | | | | | Encryp | | | |
| tion | | | | | tion | | | |
| Stand | | | | | Stand | | | |
| ard(AES | | | | | ard(AES | | | |
| ) usin | | | | | ) usin | | | |
| g 256 | | | | | g 256 | | | |
| bitkeys | | | | | bitkeys | | | |
| inCiph | | | | | inCiph | | | |
| er Bloc | | | | | er Bloc | | | |
| k Chai | | | | | k Chai | | | |
| ningmod | | | | | ning(CB | | | |
| e | | | | | C) mod | | | |
| e usi | | | |
| ng PKC | | | |
| S #5pad | | | |
| ding | | | |
| Advance | A128G | http://www.w3.org/2009/xm | AES/GCM/NoPadding | | Advance | A128G | http://www.w3.org/2009/xm | AES/GCM/NoPadding |
| d | CM | lenc11#aes128-gcm | | | d | CM | lenc11#aes128-gcm | |
| Encryp | | | | | Encryp | | | |
| tion | | | | | tion | | | |
| Stand | | | | | Stand | | | |
| ard(AES | | | | | ard(AES | | | |
| ) usin | | | | | ) usin | | | |
| g 128 | | | | | g 128 | | | |
| bitkeys | | | | | bitkeys | | | |
| inGalo | | | | | inGalo | | | |
| is/Coun | | | | | is/Coun | | | |
| ter Mod | | | | | ter Mod | | | |
| e | | | | | e (GC | | | |
| M) | | | |
| Advance | A256G | http://www.w3.org/2009/xm | AES/GCM/NoPadding | | Advance | A256G | http://www.w3.org/2009/xm | AES/GCM/NoPadding |
| d | CM | lenc11#aes256-gcm | | | d | CM | lenc11#aes256-gcm | |
| Encryp | | | | | Encryp | | | |
| tion | | | | | tion | | | |
| Stand | | | | | Stand | | | |
| ard(AES | | | | | ard(AES | | | |
| ) usin | | | | | ) usin | | | |
| g 256 | | | | | g 256 | | | |
| bitkeys | | | | | bitkeys | | | |
| inGalo | | | | | inGalo | | | |
| is/Coun | | | | | is/Coun | | | |
| ter Mod | | | | | ter Mod | | | |
| e | | | | | e (GC | | | |
| M) | | | |
+---------+-------+---------------------------+---------------------+ +---------+-------+---------------------------+---------------------+
Table 5: Encryption Algorithm Identifier Cross-Reference
Appendix C. Acknowledgements Appendix C. Acknowledgements
Solutions for signing and encrypting JSON content were previously Solutions for signing and encrypting JSON content were previously
explored by Magic Signatures [MagicSignatures], JSON Simple Sign explored by Magic Signatures [MagicSignatures], JSON Simple Sign
[JSS], Canvas Applications [CanvasApp], JSON Simple Encryption [JSE], [JSS], Canvas Applications [CanvasApp], JSON Simple Encryption [JSE],
and JavaScript Message Security Format [I-D.rescorla-jsms], all of and JavaScript Message Security Format [I-D.rescorla-jsms], all of
which influenced this draft. Dirk Balfanz, John Bradley, Yaron Y. which influenced this draft. Dirk Balfanz, John Bradley, Yaron Y.
Goland, John Panzer, Nat Sakimura, and Paul Tarjan all made Goland, John Panzer, Nat Sakimura, and Paul Tarjan all made
significant contributions to the design of this specification and its significant contributions to the design of this specification and its
related specifications. related specifications.
Appendix D. Document History Appendix D. Document History
-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.
o Defined KDF output key sizes.
o Specified the use of PKCS #5 padding with AES-CBC.
o Generalized text to allow key agreement to be employed as an
alternative to key wrapping or key encryption.
o Clarified that ECDH-ES is a key agreement algorithm.
o Required implementation of AES-128-KW and AES-256-KW.
o Removed the use of "A128GCM" and "A256GCM" for key wrapping.
o Removed "A512KW" since it turns out that it's not a standard
algorithm.
o Clarified the relationship between "typ" header parameter values
and MIME types.
o Generalized language to refer to Message Authentication Codes
(MACs) rather than Hash-based Message Authentication Codes (HMACs)
unless in a context specific to HMAC algorithms.
o Established registries: JSON Web Signature and Encryption Header
Parameters, JSON Web Signature and Encryption Algorithms, JSON Web
Signature and Encryption "typ" Values, JSON Web Key Parameters,
and JSON Web Key Algorithm Families.
o Moved algorithm-specific definitions from JWK to JWA.
o Reformatted to give each member definition its own section
heading.
-01 -01
o Moved definition of "alg":"none" for JWSs here from the JWT o Moved definition of "alg":"none" for JWSs here from the JWT
specification since this functionality is likely to be useful in specification since this functionality is likely to be useful in
more contexts that just for JWTs. more contexts that just for JWTs.
o Added Advanced Encryption Standard (AES) Key Wrap Algorithm using o Added Advanced Encryption Standard (AES) Key Wrap Algorithm using
512 bit keys ("A512KW"). 512 bit keys ("A512KW").
o Added text "Alternatively, the Encoded JWS Signature MAY be o Added text "Alternatively, the Encoded JWS Signature MAY be
 End of changes. 90 change blocks. 
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