JOSE Working Group M. Jones Internet-Draft Microsoft Intended status: Standards Track~~May 12,~~July 6,2012 Expires:~~November 13, 2012~~January 7, 2013JSON Web Algorithms (JWA)~~draft-ietf-jose-json-web-algorithms-02~~draft-ietf-jose-json-web-algorithms-03Abstract The JSON Web Algorithms (JWA) specification enumerates cryptographic algorithms and identifiers to be used with the JSON Web Signature~~(JWS) and~~(JWS),JSON Web Encryption~~(JWE) specifications. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",~~(JWE),and~~"OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].~~JSON Web Key (JWK) specifications.Status of this Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts 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 Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on~~November 13, 2012.~~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/license-info) 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 . . . . . . . . . . . . . . . . . . . . . . . . . 41.1. Notational Conventions . . . . . . . . . . . . . . . . . . 42. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 42.1. 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 . . . . . . . . . . . . . . . . . . . . . . 73. Cryptographic Algorithms for JWS . . . . . . . . . . . . . . .~~4~~73.1. "alg" (Algorithm) Header Parameter Values for JWS . . . .~~4~~73.2. MAC with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 . . .~~5~~83.3. Digital Signature with RSA SHA-256, RSA SHA-384, or RSA SHA-512 . . . . . . . . . . . . . . . . . . . . . . .~~6~~93.4. Digital Signature with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512 . . . . . . . . . .~~7~~103.5.~~Creating a Plaintext JWS .~~Using the Algorithm "none". . . . . . . . . . . . . . . .~~9~~113.6. Additional Digital Signature/MAC Algorithms and Parameters . . . . . . . . . . . . . . . . . . . . . . . .~~9~~124. Cryptographic Algorithms for JWE . . . . . . . . . . . . . . .~~9~~124.1. "alg" (Algorithm) Header Parameter Values for JWE . . . .~~9~~124.2. "enc" (Encryption Method) Header Parameter Values for JWE . . . . . . . . . . . . . . . . . . . . . . . . . . .~~10~~134.3. "int" (Integrity Algorithm) Header Parameter Values for JWE . . . . . . . . . . . . . . . . . . . . . . . . .~~11~~144.4.~~Key Encryption with RSA using RSA-PKCS1-1.5 Padding~~"kdf" (Key Derivation Function) Header Parameter Values for JWE. . .~~11~~. . . . . . . . . . . . . . . . . . . 144.5. Key Encryption with~~RSA using Optimal Asymmetric Encryption Padding (OAEP)~~RSAES-PKCS1-V1_5. . . . . . . . . . .15 4.6. Key Encryption with RSAES OAEP. . . . .~~11 4.6.~~. . . . . . . . . 15 4.7.Key Agreement with Elliptic Curve Diffie-Hellman Ephemeral Static (ECDH-ES) . . . . . . . . . . . . . . . .~~12 4.7.~~15 4.8.Key Encryption with AES Key Wrap . . . . . . . . . . . . .~~12 4.8.~~15 4.9.Plaintext Encryption with AES~~Cipher Block Chaining (CBC)~~CBCMode . . . . . . . . . .15 4.10. Plaintext Encryption with AES GCM. . . . . . . . . . . .~~. . 12 4.9. Plaintext Encryption with AES Galois/Counter Mode (GCM) . 12 4.10.~~16 4.11.Integrity Calculation with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 . . . . . . . . . . . . . . . . . . . . .~~13 4.11. Additional Encryption Algorithms~~16 4.12. Key Derivation with Concat KDFand~~Parameters~~SHA-256, SHA-384, or SHA-512. . . . .~~13 5.~~. . . . . . . . . . . . . . . . . . . 16 4.13. Additional Encryption Algorithms and Parameters . . . . . 17 5.Cryptographic Algorithms for JWK . . . . . . . . . . . . . . .~~13~~185.1. "alg" (Algorithm Family) Parameter Values for JWK . . . .~~14~~185.2. JWK Parameters for Elliptic Curve Keys . . . . . . . . . .~~14~~185.2.1. "crv" (Curve) Parameter . . . . . . . . . . . . . . .~~14~~185.2.2. "x" (X Coordinate) Parameter . . . . . . . . . . . . .~~14~~195.2.3. "y" (Y Coordinate) Parameter . . . . . . . . . . . . .~~14~~195.3. JWK Parameters for RSA Keys . . . . . . . . . . . . . . .~~14~~195.3.1. "mod" (Modulus) Parameter . . . . . . . . . . . . . .~~15~~195.3.2. "exp" (Exponent) Parameter . . . . . . . . . . . . . .~~15~~195.4. Additional Key Algorithm Families and Parameters . . . . .~~15~~196. IANA Considerations . . . . . . . . . . . . . . . . . . . . .~~15~~206.1. JSON Web Signature and Encryption~~Header Parameters~~AlgorithmsRegistry . .20 6.1.1. Registration Template. . . . . . . . . . . . . . . .21 6.1.2. Initial Registry Contents. . . . . . .~~15~~. . . . . . . 216.2. JSON Web~~Signature and Encryption Algorithms~~Key Algorithm FamiliesRegistry . .~~15 6.3. JSON Web Signature and Encryption "typ" Values Registry~~.~~16 6.4. JSON Web Key Parameters~~. . . . . . 26 6.2.1. Registration Template . . . . . . . . . . . . . . . . 26 6.2.2. InitialRegistryContents. . . . . . . . . . . . .~~16 6.5.~~. 27 6.3.JSON Web Key~~Algorithm Families~~Parameters Registration . . . . . . . . . . . 27 6.3.1.RegistryContents. . . . . . . . .~~16~~. . . . . . . . . 277. Security Considerations . . . . . . . . . . . . . . . . . . .~~16~~288. Open Issues~~and Things To Be Done (TBD)~~. . . . . . . . . . .~~17~~. . . . . . . . . . . . . . 299. References . . . . . . . . . . . . . . . . . . . . . . . . . .~~17~~299.1. Normative References . . . . . . . . . . . . . . . . . . .~~17~~299.2. Informative References . . . . . . . . . . . . . . . . . .~~18~~31Appendix A. Digital Signature/MAC Algorithm Identifier Cross-Reference . . . . . . . . . . . . . . . . . . .~~19~~32Appendix B. Encryption Algorithm Identifier Cross-Reference . . .~~21~~34Appendix C. Acknowledgements . . . . . . . . . . . . . . . . . .~~25~~36Appendix D. Document History . . . . . . . . . . . . . . . . . .~~25~~36Author's Address . . . . . . . . . . . . . . . . . . . . . . . . .~~26~~391. Introduction The JSON Web Algorithms (JWA) specification enumerates cryptographic algorithms and identifiers to be used with the JSON Web Signature (JWS)~~[JWS] and~~[JWS],JSON Web Encryption (JWE)~~[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~~JWS, JWE,and~~JWE~~JWKspecifications, 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~~1.1. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY",and~~operations that~~"OPTIONAL" in this documentare~~specific~~to~~these algorithms and algorithm families.~~be interpreted as described in Key words for use in RFCs to Indicate Requirement Levels [RFC2119].2. Terminology~~This specification uses~~2.1. Terms Incorporated fromthe~~terminology~~JWS Specification These termsdefined by the JSON Web Signature (JWS) [JWS]~~and~~specification are incorporated into this specification:JSON Web~~Encryption (JWE) [JWE] specifications. 3. Cryptographic Algorithms for~~Signature (JWS) A data structure cryptographically securing aJWSHeader and aJWS~~uses cryptographic algorithms to digitally sign~~Payload with a JWS Signature value. JWS Header A string representing a JavaScript Object Notation (JSON) [RFC4627] object that describes the digital signatureor MACoperation 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 securesthe contents of the JWS Header and the JWS Payload.~~The use~~Encoded JWS Header Base64url encodingof the~~following algorithms for producing JWSs is defined in this section. 3.1. "alg" (Algorithm) Header Parameter Values for~~bytes of the UTF-8 [RFC3629] representation of the JWS Header. Encoded JWS Payload Base64url encoding of the JWS Payload. Encoded JWS Signature Base64url encoding of the JWS Signature.JWSSecured InputThe~~table below is~~concatenation ofthe~~set~~Encoded JWS Header, a period ('.') character, and the Encoded JWS Payload. Base64url Encoding For the purposesof~~"alg" (algorithm) header parameter values defined by~~this~~specification for use~~specification, this term always refers to the URL- and filename-safe Base64 encoding described in RFC 4648 [RFC4648], Section 5,with~~JWS, each~~the (non URL- safe) '=' padding characters omitted, as permitted by Section 3.2. (See Appendix Cof~~which is explained in more detail~~[JWS] for notes on implementing base64url encoding without padding.) Collision Resistant Namespace A namespace that allows names to be allocatedina manner such that they are highly unlikely to collide with other names. For instance, collision resistance can be achieved through administrative delegation of portions ofthe~~following sections: +--------------------+----------------------------------------------+ | alg Parameter | Digital Signature~~namespaceor~~MAC Algorithm | | Value | | +--------------------+----------------------------------------------+ | HS256 | HMAC using SHA-256 hash algorithm | | HS384 | HMAC using SHA-384 hash algorithm | | HS512 | HMAC~~through use of collision-resistant name allocation functions. Examples of Collision Resistant Namespaces include: Domain Names, Object Identifiers (OIDs) as defined in the ITU-T X.660 and X.670 Recommendation series, and Universally Unique IDentifiers (UUIDs) [RFC4122]. Whenusing~~SHA-512 hash algorithm | | RS256 | RSA using SHA-256 hash algorithm | | RS384 | RSA using SHA-384 hash algorithm | | RS512 | RSA using SHA-512 hash algorithm | | ES256 | ECDSA using P-256 curve and SHA-256 hash | | | algorithm | | ES384 | ECDSA using P-384 curve and SHA-384 hash | | | algorithm | | ES512 | ECDSA using P-521 curve and SHA-512 hash | | | algorithm | | none | No digital signature or MAC value included | +--------------------+----------------------------------------------+ See Appendix A for a table cross-referencing~~an administratively delegated namespace,the~~digital signature and MAC "alg" (algorithm) values used~~definer of a name needs to take reasonable precautions to ensure they arein~~this specification with~~control ofthe~~equivalent identifiers used by other standards and software packages. Of these algorithms, only HMAC SHA-256 and "none" MUST be implemented by conforming JWS implementations. It is RECOMMENDED that implementations also support~~portion ofthe~~RSA SHA-256 and ECDSA P-256 SHA-256 algorithms. Support for other algorithms and key sizes is OPTIONAL. 3.2. MAC with HMAC SHA-256, HMAC SHA-384, or HMAC SHA-512 Hash-based Message Authentication Codes (HMACs) enable one to~~namespace theyuse~~a secret plus a cryptographic hash function~~to~~generate a Message Authentication Code (MAC). This can be used to demonstrate that the MAC matches~~definethe~~hashed content, in this case~~name. 2.2. Terms Incorporated fromthe~~JWS Secured Input, which therefore demonstrates that whoever generated~~JWE Specification These terms defined bythe~~MAC was in possession~~JSON Web Encryption (JWE) [JWE] specification are incorporated into this specification: JSON Web Encryption (JWE) A data structure representing an encrypted versionof~~the secret.~~a Plaintext.The~~means~~structure consistsof~~exchanging~~four parts:the~~shared key is outside~~JWE Header,the~~scope of this specification. The algorithm for implementing and validating HMACs is provided in RFC 2104 [RFC2104]. This section defines the use of~~JWE Encrypted Key,the~~HMAC SHA- 256, HMAC SHA-384, and HMAC SHA-512 cryptographic hash functions as defined in FIPS 180-3 [FIPS.180-3]. The "alg" (algorithm) header parameter values "HS256", "HS384",~~JWE Ciphertext,and~~"HS512" are used in~~the~~JWS Header~~JWE Integrity Value. Plaintext The bytesto~~indicate that~~be encrypted - a.k.a.,the~~Encoded JWS Signature contains a base64url encoded HMAC value using~~message. The plaintext can contain an arbitrary sequence of bytes. Ciphertext The encrypted version ofthe~~respective hash function.~~Plaintext. Content Encryption Key (CEK)Asymmetrickey~~of the same size as~~used to encryptthe~~hash output (for instance, 256 bits~~Plaintextfor~~"HS256") or larger MUST be~~the recipient to produce the Ciphertext. Content Integrity Key (CIK) A keyused with~~this algorithm. The HMAC SHA-256~~aMAC~~is generated as follows: 1. Apply the HMAC SHA-256 algorithm~~functiontoensurethe~~bytes of the UTF-8 representation~~integrityof the~~JWS Secured Input (which is the same as the ASCII representation) using~~Ciphertext andthe~~shared key~~parameters usedto~~produce an HMAC value. 2. Base64url encode~~create it. Content Master Key (CMK) A key from whichthe~~resulting HMAC value. The output is~~CEK and CIK are derived. When key wrapping or key encryption are employed,the~~Encoded JWS Signature for that JWS. The HMAC SHA-256 MAC for a JWS~~CMKis~~validated as follows: 1. Apply the HMAC SHA-256 algorithm~~randomly generated and encryptedto the~~bytes of the UTF-8 representation of~~recipient asthe~~JWS Secured Input (which~~JWE Encrypted Key. When key agreementisemployed,the~~same as~~CMK isthe~~ASCII representation)~~resultof the~~JWS using~~key agreement algorithm. JWE Header A string representing a JSON object that describesthe~~shared key. 2. Base64url encode~~encryption operations applied to createthe~~resulting HMAC value. 3. If~~JWE Encrypted Key,the~~Encoded JWS Signature~~JWE Ciphertext,and the~~base64url encoded HMAC value exactly match, then one has confirmation that the shared~~JWE Integrity Value. JWE Encrypted Key Whenkey~~was used to generate~~wrapping or key encryption are employed,the~~HMAC on~~Content Master Key (CMK) is encrypted withthe~~JWS~~intended recipient's keyand~~that the contents of~~the~~JWS have not be tampered with. 4. If~~resulting encrypted content is recorded as a byte array, which is referred to asthe~~validation fails,~~JWE Encrypted Key. Otherwise, when key agreement is employed,the~~JWS MUST be rejected. Alternatively,~~JWE Encrypted Key isthe~~Encoded JWS Signature MAY be base64url decoded to produce~~empty byte array. JWE Ciphertext A byte array containingthe~~JWS Signature and this~~Ciphertext. JWE Integrity Value A byte array containing a MACvalue~~can be compared with the computed HMAC value, as this comparison produces the same result as comparing~~that ensuresthe~~encoded values. Securing content with~~integrity ofthe~~HMAC SHA-384~~Ciphertextand~~HMAC SHA-512 algorithms is performed identically~~the parameters usedtocreate it. Encoded JWE Header Base64url encoding ofthe~~procedure for HMAC SHA-256 - just with correspondingly larger minimum key sizes and result values. 3.3. Digital Signature with RSA SHA-256, RSA SHA-384, or RSA SHA-512 This section defines~~bytes ofthe~~use~~UTF-8 [RFC3629] representationof the~~RSASSA-PKCS1-v1_5 digital 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~~JWE Header. Encoded JWE Encrypted Key Base64url encoding ofthe~~hash function. The RSASSA-PKCS1-v1_5~~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] encryptionalgorithm is~~described in FIPS 186-3 [FIPS.186-3], Section 5.5, and~~one that provides an integrated content integrity check. AES Galois/Counter Mode (GCM) is one such algorithm. 2.3. Terms Incorporated fromthe~~SHA-256, SHA-384, and SHA- 512 cryptographic hash functions are~~JWK Specification These termsdefined~~in FIPS 180-3 [FIPS.180-3]. The "alg" (algorithm) header parameter values "RS256", "RS384", and "RS512" are used in~~bythe~~JWS Header to indicate~~JSON Web Key (JWK) [JWK] specification are incorporated into this specification: JSON Web Key (JWK) A JSON data structurethat~~the Encoded JWS Signature contains~~representsa~~base64url encoded RSA digital signature using the respective hash function.~~public key. JSON Web Key Set (JWK Set)A~~key of size 2048 bits or larger MUST be used with these algorithms. Note~~JSON objectthat~~while Section 8~~contains an arrayof~~RFC 3447 [RFC3447] explicitly calls for people not to adopt RSASSA-PKCS1 for new applications and instead requests that people transition to RSASSA-PSS,~~JWKs as a member. 2.4. Defined Terms These terms are definedfor~~interoperability reasons, this specification does~~use~~RSASSA-PKCS1 because it commonly implemented.~~by this specification: Header Parameter NameThe~~RSA SHA-256 digital signature is generated as follows: 1. Generate~~name ofa~~digital signature~~memberof the~~bytes~~JSON object representing a JWS Header or JWE Header. Header Parameter Value The valueof~~the UTF-8 representation~~a memberof theJSON object representing aJWS~~Secured Input (which is~~Header or JWE Header. 3. Cryptographic Algorithms for JWS JWS uses cryptographic algorithms to digitally sign or create a Message Authentication Codes (MAC) ofthe~~same as~~contents ofthe~~ASCII representation) using RSASSA-PKCS1-V1_5-SIGN~~JWS Headerand the~~SHA- 256 hash function with the desired private key.~~JWS Payload.The~~output will be a byte array. 2. Base64url encode~~use ofthe~~resulting byte array. The output~~following algorithms for producing JWSsis~~the Encoded JWS Signature~~defined in this section. 3.1. "alg" (Algorithm) Header Parameter Valuesfor~~that JWS.~~JWSThe~~RSA SHA-256 digital signature for a JWS~~table belowis~~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 UTF-8 representation~~setof~~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 RSASSA-PKCS1-V1_5-VERIFY algorithm using SHA-256 as the hash function. 3. If the validation fails, the JWS MUST be rejected. Signing with the RSA SHA-384 and RSA SHA-512 algorithms is performed identically to the procedure for RSA SHA-256 - just with correspondingly larger result values. 3.4. Digital Signature with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512 The Elliptic Curve Digital Signature Algorithm (ECDSA) is~~"alg" (algorithm) header parameter valuesdefined by~~FIPS 186-3 [FIPS.186-3]. ECDSA provides~~this specificationfor~~the~~usewith JWS, eachof~~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~~explained in more detailin~~terms of length than equivalently strong RSA digital signatures. This specification defines the use of ECDSA with the P-256 curve and~~thefollowing sections: +--------------+--------------------------------+-------------------+ | alg | Digital Signature or MAC | Implementation | | Parameter | Algorithm | Requirements | | Value | | | +--------------+--------------------------------+-------------------+ | HS256 | HMAC usingSHA-256~~cryptographic~~hash~~function, ECDSA with the P-384 curve and the~~| REQUIRED | | | algorithm | | | HS384 | HMAC usingSHA-384 hash~~function, and ECDSA with the P-521 curve and the~~| OPTIONAL | | | algorithm | | | HS512 | HMAC usingSHA-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 "ES256", "ES384", and "ES512" are used in the JWS Header to indicate that the Encoded JWS Signature contains a base64url encoded~~| OPTIONAL | | | algorithm | | | RS256 | RSASSA using SHA-256 hash | RECOMMENDED | | | algorithm | | | RS384 | RSASSA using SHA-384 hash | OPTIONAL | | | algorithm | | | RS512 | RSASSA using SHA-512 hash | OPTIONAL | | | algorithm | | | ES256 |ECDSAusingP-256~~SHA-256,~~curve and | RECOMMENDED+ | | | SHA-256 hash algorithm | | | ES384 |ECDSAusingP-384~~SHA-384, or~~curve and | OPTIONAL | | | SHA-384 hash algorithm | | | ES512 |ECDSAusingP-521curve and | OPTIONAL | | |SHA-512~~digital signature, respectively. A key of size 160 bits or larger MUST be used with these algorithms. The ECDSA P-256 SHA-256~~hash algorithm | | | none | Nodigital signature~~is generated as follows: 1. Generate~~or MAC | REQUIRED | | | value included | | +--------------+--------------------------------+-------------------+ All the names are short becausea~~digital signature~~core goalofJWS is forthe~~bytes~~representations to be compact. However, there is no a priori length restriction on "alg" values. The useof"+" inthe~~UTF-8 representation of~~Implementation Requirements indicates thatthe~~JWS Secured Input (which~~requirement strengthislikely to be increased in a future version ofthe~~same as~~specification. See Appendix A for a table cross-referencingthe~~ASCII representation) using ECDSA P-256 SHA-256~~digital signature and MAC "alg" (algorithm) values used in this specificationwith the~~desired private key. The output will be the EC point (R, S), where R and S are unsigned integers. 2. Turn R~~equivalent identifiers used by other standardsand~~S into byte arrays in big endian order. Each array will~~software packages. 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 secret plus a cryptographic hash function to generate a Message Authentication Code (MAC). This canbe~~32 bytes long. 3. Concatenate~~used to demonstrate thatthe~~two byte arrays~~MAC matches the hashed content,inthis casethe~~order R and then S. 4. Base64url encode~~JWS Secured Input, which therefore demonstrates that whoever generatedthe~~resulting 64 byte array.~~MAC was in possession of the secret.The~~output~~means of exchanging the shared keyisoutsidethe~~Encoded JWS Signature~~scope of this specification. The algorithmforimplementing and validating HMACs is provided in RFC 2104 [RFC2104]. This section definesthe~~JWS.~~use of the HMAC SHA- 256, HMAC SHA-384, and HMAC SHA-512 functions [SHS].The~~ECDSA P-256 SHA-256 digital signature for a~~"alg" (algorithm) header parameter values "HS256", "HS384", and "HS512" are used in theJWS~~is validated as follows: 1. Take~~Header to indicate thatthe Encoded JWS Signature~~and base64url decode it into~~containsa~~byte array. If decoding fails,~~base64url encoded HMAC value usingthe~~JWS~~respective hash function. A key of the same size as the hash output (for instance, 256 bits for "HS256") or largerMUST be~~rejected. 2.~~used with this algorithm.The~~output~~HMAC SHA-256 MAC is generated per RFC 2104, using SHA-256 as the hash algorithm "H", using the bytesof the~~base64url decoding MUST be a 64 byte array. 3. Split~~ASCII [USASCII] representation ofthe~~64 byte array into two 32 byte arrays. The first array will be R~~JWS Secured Input as the "text" value,andusingthe~~second S (with both being in big endian byte order). 4. Submit~~shared key. The HMAC output value is the JWS Signature. The JWS signature is base64url encoded to produce the Encoded JWS Signature. The HMAC SHA-256 MAC for a JWS is validated by computing an HMAC value per RFC 2104, using SHA-256 as the hash algorithm "H", usingthe bytes of the~~UTF-8~~ASCIIrepresentation of thereceivedJWS Secured~~Input (which is the same~~inputas the~~ASCII representation), R, S~~"text" value,andusingthe~~public key (x, y)~~shared key. This computed HMAC value is then comparedto the~~ECDSA P-256 SHA-256 validator. 5. If the validation fails,~~result of base64url decodingthereceived EncodedJWS~~MUST be rejected. The ECDSA validator will then determine if the digital signature is valid, given~~signature. Alternatively,the~~inputs. Note that ECDSA digital signature contains a~~computed HMACvalue~~referred~~can be base64url encoded and comparedtothe received Encoded JWS Signature,as~~K, which is a random number generated for each digital signature instance. This means that two ECDSA digital signatures using exactly~~this comparison producesthe same~~input parameters will output different signature values because their K~~result as comparing the unencoded values. In either case, if thevalues~~will be different. The consequence of this is that one must validate an ECDSA digital signature by submitting~~match,the~~previously specified inputs to an ECDSA validator. Signing~~HMAC has been validated. If the validation fails, the JWS MUST be rejected. Securing contentwith the~~ECDSA P-384~~HMACSHA-384 and~~ECDSA P-521~~HMACSHA-512 algorithms is performed identically to the procedure for~~ECDSA P-256~~HMACSHA-256 - just~~with correspondingly~~using the corresponding hash algorithm with correspondinglylargerminimum key sizes andresult~~values. 3.5. Creating a Plaintext JWS To support~~values: 384 bits each for HMAC SHA-384 and 512 bits each for HMAC SHA-512. 3.3. Digital Signature with RSA SHA-256, RSA SHA-384, or RSA SHA-512 This section defines theuse~~cases where~~ofthe~~content is secured by a means other than a~~RSASSA-PKCS1-V1_5digital signaturealgorithm as defined in Section 8.2 of RFC 3447 [RFC3447], (commonly known as PKCS #1), using SHA-256, SHA-384,or~~MAC value, JWSs MAY also be created without them. These are called "Plaintext JWSs". Plaintext JWSs MUST use~~SHA-512 [SHS] asthehash functions. The"alg"~~value "none",~~(algorithm) header parameter values "RS256", "RS384",and"RS512"are~~formatted identically~~used in the JWS Headerto~~other JWSs, but with an empty~~indicate that the EncodedJWS Signature~~value. 3.6. Additional Digital Signature/MAC Algorithms and Parameters Additional algorithms MAY~~contains a base64url encoded RSA digital signature using the respective hash function. A key of size 2048 bits or larger MUSTbe 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~~these algorithms. The RSA SHA-256 digital signature is generated as follows: 1. Generate a digital signature ofthe~~IANA JSON Web Signature~~bytes of the ASCII representation of the JWS Secured Input using RSASSA-PKCS1-V1_5- SIGNand~~Encryption Algorithms registry Section 6.2 or~~the SHA-256 hash function with the desired private key. The output willbe a~~URI~~byte array. 2. Base64url encode the resulting byte array. The output is the Encoded JWS Signature forthat~~contains~~JWS. The RSA SHA-256 digital signature fora~~collision resistant namespace. In particular, it~~JWSis~~permissible to use the algorithm identifiers defined in XML DSIG [RFC3275], XML DSIG 2.0 [W3C.CR-xmldsig-core2-20120124], and related specifications~~validatedas~~"alg" values. As indicated by~~follows: 1. Takethe~~common registry, JWSs~~Encoded JWS Signatureand~~JWEs share~~base64url decode it intoa~~common "alg" value space. The values used by~~byte array. If decoding fails,the~~two specifications~~JWSMUST be~~distinct, as~~rejected. 2. Submitthe~~"alg" value MAY be used to determine whether~~bytes ofthe~~object is a JWS or JWE. Likewise, additional reserved header parameter names MAY be defined via~~ASCII representation ofthe~~IANA JSON Web Signature~~JWS Secured Inputand~~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~~public key corresponding to the private keyused by~~both specifications, its usage must~~the signer to the RSASSA-PKCS1-V1_5-VERIFY algorithm using SHA- 256 as the hash function. 3. If the validation fails, the JWS MUSTbe~~compatible between~~rejected. Signing withthe~~specifications. 4. Cryptographic Algorithms for JWE JWE uses cryptographic~~RSA SHA-384 and RSA SHA-512algorithmsis performed identicallyto~~encrypt~~the~~Content Master Key (CMK) and~~procedure for RSA SHA-256 - just usingthe~~Plaintext. This section specifies a set of specific algorithms~~corresponding hash algorithm with correspondingly larger result values: 384 bitsfor~~these purposes. 4.1. "alg" (Algorithm) Header Parameter Values~~RSA SHA-384 and 512 bitsfor~~JWE~~RSA SHA-512. 3.4. Digital Signature with ECDSA P-256 SHA-256, ECDSA P-384 SHA-384, or ECDSA P-521 SHA-512The~~table below is~~Elliptic Curve Digital Signature Algorithm (ECDSA) [DSS] provides forthe~~set~~useof~~"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~~Elliptic Curve cryptography, which is ableto~~use key agreement~~provide equivalent securityto~~agree upon the CMK. +-----------+-------------------------------------------------------+ | alg | Key Encryption or Agreement Algorithm | | Parameter | | | Value | | +-----------+-------------------------------------------------------+ | RSA1_5 |~~RSAcryptography butusing~~RSA-PKCS1-1.5 padding, as defined~~shorter key sizes and with greater processing speed. This means that ECDSA digital signatures will be substantially smallerin~~RFC | | | 3447 [RFC3447] | | RSA-OAEP |~~terms of length than equivalently strongRSA~~using Optimal Asymmetric Encryption Padding | | | (OAEP), as defined in RFC 3447 [RFC3447] | | ECDH-ES | Elliptic Curve Diffie-Hellman Ephemeral Static, as | | | defined in RFC 6090 [RFC6090], and using~~digital signatures. This specification definesthe~~Concat | | | KDF, as defined in Section 5.8.1~~useof~~[NIST.800-56A], | | | where~~ECDSA with the P-256 curve andthe~~Digest Method is~~SHA-256cryptographic hash function, ECDSA with the P-384 curveand~~all OtherInfo | | | parameters are~~the~~empty bit string | | A128KW | Advanced Encryption Standard (AES) Key Wrap Algorithm | | | using 128 bit keys, as~~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 aredefined in~~RFC 3394 [RFC3394] | | A256KW | Advanced Encryption Standard (AES) Key Wrap Algorithm | | | using 256 bit keys, as defined~~[DSS]. The "alg" (algorithm) header parameter values "ES256", "ES384", and "ES512" are usedin~~RFC 3394 [RFC3394] | +-----------+-------------------------------------------------------+ 4.2. "enc" (Encryption Method)~~the JWSHeader~~Parameter Values for JWE~~to indicate 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 signature, respectively.The~~table below~~ECDSA P-256 SHA-256 digital signatureisgenerated as follows: 1. Generate a digital signature ofthe~~set~~bytesof~~"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~~ASCII representation ofthe~~Ciphertext. +-----------+-------------------------------------------------------+ | enc | Block Encryption Algorithm | | Parameter | | | Value | | +-----------+-------------------------------------------------------+ | A128CBC | Advanced Encryption Standard (AES) using 128 bit keys | | | in Cipher Block Chaining (CBC) mode~~JWS Secured Inputusing~~PKCS #5 | | | padding, as defined in [FIPS.197]~~ECDSA P-256 SHA-256 with the desired private key. The output will be the EC point (R, S), where Rand~~[NIST.800-38A] | | A256CBC | Advanced Encryption Standard (AES) using 256 bit keys | | | in Cipher Block Chaining (CBC) mode using PKCS #5 | | | padding, as defined in [FIPS.197]~~S are unsigned integers. 2. Turn Rand~~[NIST.800-38A] | | A128GCM | Advanced Encryption Standard (AES) using 128 bit keys | | |~~S into byte arraysin~~Galois/Counter Mode (GCM), as defined~~big endian order, with each array being be 32 bytes long. 3. Concatenate the two byte arraysin~~| | | [FIPS.197]~~the order Rand~~[NIST.800-38D] | | A256GCM | Advanced Encryption Standard (AES) using 256 bit keys | | | in Galois/Counter Mode (GCM),~~then S. (Note that many ECDSA implementations will directly produce this concatenationas~~defined in | | | [FIPS.197] and [NIST.800-38D] | +-----------+-------------------------------------------------------+ See Appendix B~~their output.) 4. Base64url encode the resulting 64 byte array. The output is the Encoded JWS Signature for the JWS. The ECDSA P-256 SHA-256 digital signaturefor a~~table cross-referencing~~JWS is validated as follows: 1. Takethe~~encryption "alg" (algorithm)~~Encoded JWS Signatureand~~"enc" (encryption method) values used in this specification with~~base64url decode it into a byte array. If decoding fails,the~~equivalent identifiers used by other standards and software packages. Of these "alg" and "enc" algorithms, only RSA-PKCS1-1.5 with 2048 bit keys, AES-128-KW, AES-256-KW, AES-128-CBC, and AES-256-CBC~~JWSMUST be~~implemented by conforming JWE implementations. It is RECOMMENDED that implementations also support ECDH-ES with 256 bit keys, AES-128- GCM, and AES-256-GCM. Support for other algorithms and key sizes is OPTIONAL. 4.3. "int" (Integrity Algorithm) Header Parameter Values for JWE~~rejected. 2.The~~table below is the set~~outputof~~"int" (integrity algorithm) header parameter values defined by this specification for use with JWE. Note that these are~~the~~HMAC SHA subset of~~base64url decoding MUST be a 64 byte array. If decoding does not result in a 64 byte array,the~~"alg" (algorithm) header parameter values defined for use with~~JWS~~Section 3.1. /> +---------------------+-----------------------------------+ | 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~~rejected. 3. Splitthe~~RSA SHA-256~~64 byte array into two 32 byte arrays. The first array will be Rand~~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~~second S (with both beingin~~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~~big endian byte order). 4. Submitthe~~specifics~~bytesof~~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~~ASCII representationof~~[NIST.800-56A], where~~the~~Digest Method is SHA-256~~JWS Secured Input R, Sand~~all OtherInfo parameters are~~the~~empty bit string. The "alg" header parameter value "ECDH-ES" is used in this case. A~~publickey~~of size 160 bits or larger MUST be used for~~(x, y) tothe~~Elliptic Curve keys used with this algorithm. The output of~~ECDSA P-256 SHA-256 validator. 5. Ifthe~~Concat KDF~~validation fails, the JWSMUST berejected. Note that ECDSA digital signature containsa~~key of the same length~~value referred toasK, which is a random number generated for each digital signature instance. This meansthat~~used by~~two ECDSA digital signatures using exactlythe~~"enc" algorithm. An "epk" (ephemeral public key) value MUST only~~same input parameters will output different signature values because their K values willbe~~used for a single key agreement transaction. 4.7. Key Encryption with AES Key Wrap This section defines the specifics~~different. A consequenceof~~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~~is that one cannot validate an ECDSA signature by recomputingthe~~specifics of encrypting~~signature and comparingthe~~JWE Plaintext~~results. Signingwith~~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]~~the ECDSA P-384 SHA-384and~~[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~~ECDSA P-521 SHA-512 algorithmsis~~RECOMMENDED with this algorithm. 4.9. Plaintext Encryption with AES Galois/Counter Mode (GCM) This section defines~~performed identically tothe~~specifics of encrypting~~procedure for ECDSA P-256 SHA-256 - just usingthe~~JWE Plaintext~~corresponding hash algorithmwith~~Advanced Encryption Standard (AES) in Galois/Counter Mode (GCM) using 128 or 256 bit keys, as defined in [FIPS.197]~~correspondingly larger result values. For ECDSA P-384 SHA-384, Rand~~[NIST.800-38D]. The "enc" header parameter values "A128GCM" or "A256GCM" are used~~S will be 48 bytes each, resultingin~~this case. Use of an Initialization Vector (IV) of size~~a96~~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,~~byte array. For ECDSA P-521 SHA-512, Rand~~the Encoded JWE Encrypted Key. The requested size of the "authentication tag" output MUST~~S willbe66 bytes each (so they can represent a 521-bit integer), resulting in a 132 byte array. 3.5. Usingthe~~same as the key size (for instance, 128 bits for "A128GCM"). As GCM is an AEAD algorithm, the JWE Integrity Value is set to~~Algorithm "none" JWSs MAY alsobecreated that do not provide integrity protection. Such a JWS is called a "Plaintext JWS". Plaintext JWSs MUST usethe~~"authentication tag"~~"alg"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"~~"none", andare~~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~~formatted identically to other JWSs, butwith~~this algorithm. 4.11.~~an empty JWS Signature value. 3.6.Additional~~Encryption~~Digital Signature/MACAlgorithms and Parameters Additional algorithms MAY be used to protect~~JWEs~~JWSswith corresponding "alg"~~(algorithm), "enc" (encryption method), and "int" (integrity algorithm)~~(algorithm)header parameter values being defined to refer to them. New~~"alg", "enc", and "int"~~"alg"header parameter values SHOULD either be~~defined~~registeredin the IANA JSON Web Signature and Encryption Algorithms registry Section~~6.2~~6.1or be a URI that contains a~~collision resistant namespace.~~Collision Resistant Namespace.In particular, it is permissible to use the algorithm identifiers defined in XML~~Encryption [W3C.REC-xmlenc-core-20021210],~~DSIG [RFC3275],XML~~Encryption 1.1 [W3C.CR-xmlenc-core1-20120313],~~DSIG 2.0 [W3C.CR-xmldsig-core2-20120124],and related specifications as~~"alg", "enc", and "int"~~"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.~~[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.~~4.Cryptographic Algorithms for~~JWK A JSON Web~~JWE JWE uses cryptographic algorithms to encrypt the Content MasterKey~~(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~~(CMK) and the Plaintext. This section specifiesa set of~~algorithm families to be used for those public keys and the algorithm family~~specific~~parameters~~algorithmsfor~~representing those keys. 5.1.~~these purposes. 4.1."alg"~~(Algorithm Family)~~(Algorithm) HeaderParameter Values for~~JWK~~JWEThe table below is the set of "alg"~~(algorithm family)~~(algorithm) headerparameter values that are defined by this specification for use~~in JWKs. +---------------------+----------------------------------------+~~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 | Implementation | |Parameter~~Value~~| Algorithm~~Family~~|~~+---------------------+----------------------------------------+~~Requirements|~~EC~~|~~Elliptic Curve [FIPS.186-3] key family~~Value| |~~RSA~~|~~RSA~~+-----------+--------------------------------------+----------------+ | RSA1_5 | RSAES-PKCS1-V1_5[RFC3447]~~key family~~|~~+---------------------+----------------------------------------+ 5.2. JWK Parameters for Elliptic Curve Keys 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: 5.2.1. "crv" (Curve) Parameter The "crv" (curve) member identifies the cryptographic curve used~~REQUIRED | | RSA-OAEP | RSAES using Optimal Asymmetric | OPTIONAL | | | Encryption Padding (OAEP) [RFC3447], | | | |with 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~~default parameters | | | | specifiedby~~implementations using that~~RFC 3447 in Section | | | | A.2.1 | | | ECDH-ES |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~~Diffie-Hellman | RECOMMENDED+ | | | Ephemeral Static [RFC6090], and | | | | usingthe~~elliptic curve point. It is represented~~Concat KDF,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 elliptic curve point. It is represented as the base64url encoding~~defined in | | | | Section 5.8.1of[NIST.800-56A], | | | | wherethe~~coordinate's big endian representation. 5.3. JWK Parameters for RSA Keys JWKs can represent RSA [RFC3447] keys. In this case,~~Digest Method is SHA-256 | | | | and all OtherInfo parameters arethe~~"alg" member value MUST be "RSA". Furthermore, these additional members MUST be present: 5.3.1. "mod" (Modulus) Parameter~~| | | | 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~~"mod" (modulus) member contains~~use of "+" inthe~~modulus value for~~Implementation Requirements indicates thatthe~~RSA public key. It~~requirement strengthis~~represented as the base64url encoding~~likely to be increased in a future versionof the~~value's big endian representation. 5.3.2. "exp" (Exponent)~~specification. 4.2. "enc" (Encryption Method) HeaderParameter~~The "exp" (exponent) member contains the exponent value~~Valuesfor~~the RSA public key. It~~JWE The table belowis~~represented as~~the~~base64url encoding~~setof~~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)~~"enc" (encryption method) headerparameter values~~being~~that aredefinedby this specification for use with JWE. These algorithms are usedto~~refer to them. New "alg" parameter values SHOULD either be defined in~~encryptthe~~IANA JSON Web Key~~Plaintext, which produces the Ciphertext. +-----------+--------------------------------------+----------------+ | enc | Block EncryptionAlgorithm~~Families registry Section 6.5 or be a URI that contains a collision resistant namespace. Likewise, parameters for representing~~| Implementation | | Parameter | | Requirements | | Value | | | +-----------+--------------------------------------+----------------+ | A128CBC | Advanced Encryption Standard (AES) | REQUIRED | | | in Cipher Block Chaining (CBC) mode | | | | with PKCS #5 padding [AES] | | | | [NIST.800-38A] using 128 bitkeys~~for additional algorithm families or additional key properties SHOULD either be defined~~| | | A256CBC | AES in CBC mode with PKCS #5 padding | REQUIRED | | | using 256 bit keys | | | A128GCM | AESinGalois/Counter Mode (GCM) | RECOMMENDED | | | [AES] [NIST.800-38D] using 128 bit | | | | keys | | | A256GCM | AES GCM using 256 bit keys | RECOMMENDED | +-----------+--------------------------------------+----------------+ Allthe~~IANA JSON Web Key Parameters registry Section 6.4 or~~names are short because a core goal of JWE is for the representations tobecompact. However, there is noa~~URI that contains~~priori length restriction on "alg" values. See Appendix B fora~~collision resistant namespace. 6. IANA Considerations 6.1. JSON Web Signature~~table cross-referencing the encryption "alg" (algorithm)and~~Encryption Header Parameters Registry This~~"enc" (encryption method) values used in thisspecification~~establishes~~withthe~~IANA JSON Web Signature~~equivalent identifiers used by other standardsand~~Encryption~~software packages. 4.3. "int" (Integrity Algorithm)Header~~Parameters registry~~Parameter Valuesfor~~reserved JWS and~~JWE~~header parameter names. Inclusion in the registry~~The table belowis~~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~~theset of "int" (integrity algorithm)header parameter~~names~~valuesdefined~~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~~by thisspecification~~establishes the IANA JSON Web Signature and Encryption Algorithms registry~~for~~values~~use with JWE. Note that these are the HMAC SHA subsetof the~~JWS and JWE~~"alg"~~(algorithm), "enc" (encryption method), and "int" (integrity algorithm)~~(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~~parametervalues defined~~in Section 3.1, Section 4.1, Section 4.2, and~~for use with JWSSection~~4.3. 6.3. JSON Web Signature and Encryption "typ" Values Registry This specification establishes the IANA JSON Web Signature and Encryption "typ"~~3.1. +-----------------+-------------------------+-----------------------+ | int Parameter | Algorithm | Implementation | | Value | | Requirements | +-----------------+-------------------------+-----------------------+ | HS256 | HMAC using SHA-256 hash | REQUIRED | | | algorithm | | | HS384 | HMAC using SHA-384 hash | OPTIONAL | | | algorithm | | | HS512 | HMAC using SHA-512 hash | OPTIONAL | | | algorithm | | +-----------------+-------------------------+-----------------------+ 4.4. "kdf" (Key Derivation Function) Header ParameterValues~~registry~~for~~values of the JWS and~~JWE~~"typ" (type) header parameter. Inclusion in the registry~~The table belowis~~RFC Required in~~the~~RFC 5226 [RFC5226] sense. It is RECOMMENDED that all registered "typ"~~set of "kdf" (key derivation function) header parametervalues~~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~~defined by this specificationfor~~(if any), and a pointer to~~use with JWE. +-----------+--------------------------------------+----------------+ | kdf | Algorithm | Implementation | | Parameter | | Requirements | | Value | | | +-----------+--------------------------------------+----------------+ | CS256 | Concat KDF, as defined in Section | REQUIRED | | | 5.8.1 of [NIST.800-56A], with | | | | parameters per Section 4.12, using | | | | SHA-256 asthe~~RFC that defines it. MIME Media Type RFC 2045 [RFC2045] values MUST NOT be directly registered~~digest method | | | CS384 | Concat KDF with parameters per | OPTIONAL | | | Section 4.12, using SHA-384as~~new "typ" values; rather, new "typ" values MAY be registered~~the | | | | digest method | | | CS512 | Concat KDF with parameters per | OPTIONAL | | | Section 4.12, using SHA-512as~~short names for MIME types. 6.4. JSON Web~~the | | | | digest method | | +-----------+--------------------------------------+----------------+ 4.5.Key~~Parameters Registry~~Encryption with RSAES-PKCS1-V1_5This~~specification establishes~~section definesthe~~IANA JSON Web Key Parameters registry for reserved JWK~~specifics of encrypting a JWE CMK with RSAES-PKCS1-V1_5 [RFC3447]. The "alg" headerparameter~~names. Inclusion in the registry~~value "RSA1_5"is~~RFC Required~~usedinthis case. A key of size 2048 bits or larger MUST be used with this algorithm. 4.6. Key Encryption with RSAES OAEP This section definesthe~~RFC 5226 [RFC5226] sense. The registry records the reserved parameter name and~~specifics of encryptinga~~reference to~~JWE CMK with RSAES using Optimal Asymmetric Encryption Padding (OAEP) [RFC3447], withthedefault parameters specified byRFC~~that defines it. This specification registers the parameter names defined~~3447in~~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~~A.2.1. The"alg"~~(algorithm family) parameter. Inclusion in the registry~~header parameter value "RSA-OAEP"is~~RFC Required~~usedinthis case. A key of size 2048 bits or larger MUST be used with this algorithm. 4.7. Key Agreement with Elliptic Curve Diffie-Hellman Ephemeral Static (ECDH-ES) This section definesthe~~RFC 5226 [RFC5226] sense. The registry records the "alg" value and~~specifics of agreeing upona~~pointer to the RFC that defines it. This specification registers~~JWE CMK with Elliptic Curve Diffie-Hellman Ephemeral Static [RFC6090], and usingthe~~values~~Concat KDF, asdefined in Section~~5.1. 7. Security Considerations The security considerations in~~5.8.1 of [NIST.800-56A], wherethe~~JWS, JWE,~~Digest Method is SHA-256and~~JWK specifications also apply to this specification. Eventually~~all OtherInfo parameters arethe~~algorithms and/or key sizes currently described~~empty bit string. The "alg" header parameter value "ECDH-ES" is usedin 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)~~case.The~~following items remain to~~output of the Concat KDF MUSTbe~~done in this draft: o Find values for encryption algorithm cross-reference table currently listed~~a key of the same lengthas~~"TBD" or determine~~that~~they do not exist. 9. References 9.1. Normative References [FIPS.180-3] National Institute~~used by the "enc" algorithm. A new "epk" (ephemeral public key) value MUST be generated for each key agreement transaction. 4.8. Key Encryption with AES Key Wrap This section defines the specificsof~~Standards and Technology, "Secure Hash~~encrypting a JWE CMK with the Advanced EncryptionStandard~~(SHS)", FIPS PUB 180-3, October 2008. [FIPS.186-3] National Institute of Standards and Technology, "Digital Signature Standard (DSS)", FIPS PUB 186-3, June 2009. [FIPS.197] National Institute~~(AES) Key Wrap Algorithm [RFC3394] using 128 or 256 bit keys. The "alg" header parameter values "A128KW" or "A256KW" are used in this case. 4.9. Plaintext Encryption with AES CBC Mode This section defines the specificsof~~Standards and Technology (NIST), "Advanced~~encrypting the JWE Plaintext with AdvancedEncryption Standard~~(AES)", FIPS PUB 197, November 2001. [JWE] Jones, M., Rescorla, E., and J. Hildebrand, "JSON Web Encryption (JWE)", May 2012. [JWK] Jones, M., "JSON Web Key (JWK)", May 2012. [JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Signature (JWS)", May 2012. [NIST.800-38A] National Institute of Standards and Technology (NIST), "Recommendation for Block~~(AES) inCipher~~Modes~~Block Chaining (CBC) mode with PKCS #5 padding [AES] [NIST.800-38A] using 128 or 256 bit keys. The "enc" header parameter values "A128CBC" or "A256CBC" are used in this case. Useof~~Operation", NIST PUB 800-38A, December 2001. [NIST.800-38D] National Institute~~an initialization vectorof~~Standards and Technology (NIST), "Recommendation for Block Cipher Modes~~size 128 bits is REQUIRED with this algorithm. 4.10. Plaintext Encryption with AES GCM This section defines the specificsof~~Operation:~~encrypting the JWE Plaintext with Advanced Encryption Standard (AES) inGalois/Counter Mode (GCM)~~and GMAC", NIST PUB 800-38D, December 2001. [NIST.800-56A] National Institute~~[AES] [NIST.800-38D] using 128 or 256 bit keys. The "enc" header parameter values "A128GCM" or "A256GCM" are used in this case. Useof~~Standards~~an initialization vector of size 96 bits is REQUIRED with this algorithm. The "additional authenticated data" parameter is used to secure the headerand~~Technology (NIST), "Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography (Revised)", NIST PUB 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- Hashing for Message Authentication", RFC 2104, February 1997. [RFC2119] Bradner, S., "Key words~~key values, as specifiedfor~~use~~AEAD algorithmsin~~RFCs~~Section 5 of [JWE]. 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 setto~~Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3394] Schaad, J.~~be the "authentication tag" value produced by the encryption. 4.11. 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 [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") MUST be used with this algorithm. Per Section 9 of [JWE], the JWS Secured Input value used contains the header, encrypted key,and~~R. Housley, "Advanced Encryption Standard (AES)~~ciphertext. 4.12.Key~~Wrap Algorithm", RFC 3394, September 2002. [RFC3447] Jonsson, J. and B. Kaliski, "Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1", RFC 3447, February 2003. [RFC5226] Narten, T.~~Derivation with Concat KDFand~~H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [RFC6090] McGrew, D., Igoe, K.,~~SHA-256, SHA-384, or SHA-512 The key derivation process derives CEKand~~M. Salter, "Fundamental Elliptic Curve Cryptography Algorithms", RFC 6090, February 2011. 9.2. Informative References [CanvasApp] Facebook, "Canvas Applications", 2010. [I-D.rescorla-jsms] Rescorla, E. and J. Hildebrand, "JavaScript Message Security Format", draft-rescorla-jsms-00 (work in progress), March 2011. [JCA] Oracle, "Java Cryptography Architecture", 2011. [JSE] Bradley, J. and N. Sakimura (editor), "JSON Simple Encryption", September 2010. [JSS] Bradley, J. and N. Sakimura (editor), "JSON Simple Sign", 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) XML-Signature Syntax and Processing", RFC 3275, March 2002. [W3C.CR-xmldsig-core2-20120124] 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 Wide Web Consortium CR CR-xmlenc-core1-20120313, March 2012, <http://www.w3.org/TR/2012/CR-xmlenc-core1-20120313>. [W3C.REC-xmlenc-core-20021210] Eastlake, D. and J. Reagle, "XML Encryption Syntax and Processing", World Wide Web Consortium Recommendation REC- xmlenc-core-20021210, December 2002, <http://www.w3.org/TR/2002/REC-xmlenc-core-20021210>. Appendix A. Digital Signature/MAC Algorithm Identifier Cross-Reference This appendix contains~~CIK values from the CMK. It uses asa~~table cross-referencing~~primitive a Key Derivation Function (KDF) which notionally takes three arguments: MasterKey: The master key used to computethe~~digital signature and MAC "alg" (algorithm) values~~individual use keys Label: The use key label,usedto differentiate individual use keys Length: The desired length of the use key This section defines the specifics of using the Concat KDF, as definedin~~this specification with~~Section 5.8.1 of [NIST.800-56A], wherethe~~equivalent identifiers used by other standards~~Digest Method is one of SHA-256, SHA-384, or SHA-512, the SuppPubInfo parameter is the Label,and~~software packages. See XML DSIG [RFC3275], XML DSIG 2.0 [W3C.CR-xmldsig-core2-20120124],~~the remaining OtherInfo parameters are the empty bit string. The "kdf" (key derivation function) header parameter values "CS256", "CS384",and~~Java Cryptography Architecture [JCA]~~"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 sizefor~~more information about~~the~~names~~"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 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 identifiersdefinedin 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. As indicatedby~~those documents. +-------+-----+----------------------------+----------+-------------+ | Algor |~~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 aJWSor JWE. Likewise, additional reserved header parameter names MAY be defined via the IANA JSON Web Signature and Encryption Header Parameters 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 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. +-----------------+-------------------------+-----------------------+|~~XML DSIG | JCA | OID | | ithm | | | | | +-------+-----+----------------------------+----------+-------------+ | HMAC | HS2 | http://www.w3.org/2001/04/ | HmacSHA2 | 1.2.840.113 | | using | 56 | xmldsig-more#hmac-sha256 | 56 | 549.2.9 | | SHA-2 | | | | | | 56 | | | | | | hash | | | | | | algo | | | | | | rithm | | | | | | HMAC | HS3 | http://www.w3.org/2001/04/ | HmacSHA3 | 1.2.840.113 | | using | 84 | xmldsig-more#hmac-sha384 | 84 | 549.2.10 | | SHA-3~~alg Parameter|Algorithm Family|Implementation| |Value| |~~84~~Requirements|+-----------------+-------------------------+-----------------------+|EC|Elliptic Curve [DSS]|RECOMMENDED+| |~~hash~~|key family| | |RSA|RSA [RFC3447] key|~~algo~~REQUIRED| | |family| |~~| rithm | | | | | | HMAC | HS5 | http://www.w3.org/2001/04/ | HmacSHA5 | 1.2.840.113 | |~~+-----------------+-------------------------+-----------------------+ 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 [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. Curve values from [DSS] used by this specification are: o "P-256" o "P-384" o "P-521" Additional "crv" values MAY be used, provided they are understood by implementationsusing~~| 12 | xmldsig-more#hmac-sha512 | 12 | 549.2.11 | | SHA-5 | | | | | | 12 | | | | | | hash | | | | | | algo | | | | | | rithm | | | | | |~~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 elliptic curve point. It is represented as the base64url encoding of the coordinate's big endian representation. 5.3. JWK Parameters forRSA~~| RS2 | http://www.w3.org/2001/04/ | SHA256wi | 1.2.840.113 | | using | 56 | xmldsig-more#rsa-sha256 | thRSA | 549.1.1.11 | | SHA-2 | | | | | | 56 | | | | | | hash | | | | | | algo | | | | | | rithm | | | | | |~~Keys JWKs can representRSA~~| RS3 | http://www.w3.org/2001/04/ | SHA384wi | 1.2.840.113 | |~~[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 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 unsigned big endian representation. 5.4. Additional Key Algorithm Families and Parameters Public keysusingadditional 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 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 registered in the IANA JSON Web Key Parameters registry [JWK] or be a URI that contains a Collision Resistant Namespace. 6. IANA Considerations The following registration procedure is used for all the registries established by this specification. 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. 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 RFC-EDITOR: The name of the mailing list should be determined in consultation with the IESG and IANA. Suggested name: jose-reg-review. ]] 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. 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. 6.1.1. Registration Template Algorithm Name: The name requested (e.g., "example"). Algorithm Usage Location(s): The algorithm usage, which must be one or more of the values "alg", "enc", "int", or "kdf". 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. Change Controller: For standards-track RFCs, state "IETF". For others, give the name of the responsible party. Other details (e.g., postal address, e-mail address, home page URI) may also be included. 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: "RSA-OAEP" 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: "ECDH-ES" 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. 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 standards-track RFCs, state "IETF". For others, give the name of the responsible party. Other details (e.g., postal address, e-mail 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 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.800-38A], [NIST.800-38D], [NIST.800-56A], [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. 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 SHA-256 as the integrity algorithm is recommended, whereas when AES CBC is used with a 256 bit key, using HMAC SHA-512 as the integrity algorithm is recommended. 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, this specification does include RSASSA-PKCS1, for interoperability reasons, because it commonly implemented. Keys used with RSAES-PKCS1-v1_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. 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. 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. 8. Open Issues [[ to be removed by the RFC editor before publication as an RFC ]] 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 (non-authenticated) 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 186-3, June 2009. [JWE] Jones, M., Rescorla, E., and J. Hildebrand, "JSON Web Encryption (JWE)", July 2012. [JWK] Jones, M., "JSON Web Key (JWK)", July 2012. [JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Signature (JWS)", July 2012. [NIST.800-38A] National Institute of Standards and Technology (NIST), "Recommendation for Block Cipher Modes of Operation", NIST PUB 800-38A, December 2001. [NIST.800-38D] National Institute of Standards and Technology (NIST), "Recommendation for Block Cipher Modes of Operation: Galois/Counter Mode (GCM) and GMAC", NIST PUB 800-38D, December 2001. [NIST.800-56A] National Institute of Standards and Technology (NIST), "Recommendation for Pair-Wise Key Establishment Schemes Using Discrete Logarithm Cryptography (Revised)", NIST PUB 800-56A, March 2007. [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, "Public-Key Cryptography Standards (PKCS) #1: RSA Cryptography Specifications Version 2.1", RFC 3447, February 2003. [RFC3629] Yergeau, F., "UTF-8, 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 180-3, October 2008. [USASCII] American National Standards Institute, "Coded Character Set -- 7-bit American Standard Code for Information Interchange", ANSI X3.4, 1986. 9.2. Informative References [CanvasApp] Facebook, "Canvas Applications", 2010. [I-D.rescorla-jsms] Rescorla, E. and J. Hildebrand, "JavaScript Message Security Format", draft-rescorla-jsms-00 (work in progress), March 2011. [JCA] Oracle, "Java Cryptography Architecture", 2011. [JSE] Bradley, J. and N. Sakimura (editor), "JSON Simple Encryption", September 2010. [JSS] Bradley, J. and N. Sakimura (editor), "JSON Simple Sign", 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) XML-Signature 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.CR-xmldsig-core2-20120124] 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 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., Hirsch, F., and T. Roessler, "XML Encryption Syntax and Processing Version 1.1", World Wide Web Consortium CR CR-xmlenc-core1-20120313, March 2012, <http://www.w3.org/TR/2012/CR-xmlenc-core1-20120313>. [W3C.REC-xmlenc-core-20021210] Eastlake, D. and J. Reagle, "XML Encryption Syntax and Processing", World Wide Web Consortium Recommendation REC- xmlenc-core-20021210, December 2002, <http://www.w3.org/TR/2002/REC-xmlenc-core-20021210>. Appendix A. Digital Signature/MAC Algorithm Identifier Cross-Reference This appendix contains a table cross-referencing the digital signature and MAC "alg" (algorithm) values used in this specification with the equivalent identifiers used by other standards and software packages. See XML DSIG [RFC3275], XML DSIG 2.0 [W3C.CR-xmldsig-core2-20120124], and Java Cryptography Architecture [JCA] for more information about the names defined by those documents. +-------+-----+----------------------------+----------+-------------+|~~84 | xmldsig-more#rsa-sha384 | thRSA | 549.1.1.12 | | SHA-3 | | | | | | 84 | | | | | | hash | | | | | | algo~~Algor|JWS|XML DSIG|JCA|OID| |~~rithm~~ithm| | | | |+-------+-----+----------------------------+----------+-------------+|~~RSA~~HMAC|~~RS5~~HS2| http://www.w3.org/2001/04/ |~~SHA512wi~~HmacSHA2| 1.2.840.113 | | using |~~12~~56|~~xmldsig-more#rsa-sha512~~xmldsig-more#hmac-sha256|~~thRSA~~56|~~549.1.1.13~~549.2.9| |~~SHA-5~~SHA-2| | | | | |~~12~~56| | | | | | hash | | | | | | algo | | | | | | rithm | | | | | |~~ECDSA~~HMAC|~~ES2~~HS3| http://www.w3.org/2001/04/ |~~SHA256wi~~HmacSHA3|~~1.2.840.100~~1.2.840.113| | using |~~56 | xmldsig-more#ecdsa-sha256 | thECDSA | 45.4.3.2 | | P-256 | | | | | | curve | | | | | | and |~~84|xmldsig-more#hmac-sha384|84|549.2.10| |~~SHA-2~~SHA-3| | | | | |~~56~~84| | | | | | hash | | | | | | algo | | | | | | rithm | | | | | |~~ECDSA~~HMAC|~~ES3~~HS5| http://www.w3.org/2001/04/ |~~SHA384wi~~HmacSHA5|~~1.2.840.100~~1.2.840.113| | using |~~84 | xmldsig-more#ecdsa-sha384 | thECDSA | 45.4.3.3 | | P-384 | | | | | | curve | | | | | | and |~~12|xmldsig-more#hmac-sha512|12|549.2.11| |~~SHA-3~~SHA-5| | | | | |~~84~~12| | | | | | hash | | | | | | algo | | | | | | rithm | | | | | |~~ECDSA~~RSASS|~~ES5~~RS2| http://www.w3.org/2001/04/ |~~SHA512wi | 1.2.840.100 | | using | 12 | xmldsig-more#ecdsa-sha512 | thECDSA | 45.4.3.4 | | P-521 | | | | | | curve | | | | | | and | | |~~SHA256wi|1.2.840.113| |~~SHA-5~~A|56|xmldsig-more#rsa-sha256|thRSA|549.1.1.11| |~~12~~usin| | | | | |~~hash~~gSHA-| | | | | |~~algo~~256| | | | | |~~rithm~~has| | | | |~~+-------+-----+----------------------------+----------+-------------+ Appendix B. Encryption Algorithm Identifier Cross-Reference This appendix contains a table cross-referencing 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.REC-xmlenc-core-20021210], XML Encryption 1.1 [W3C.CR-xmlenc-core1-20120313], and Java Cryptography Architecture [JCA] for more information about the names defined by those documents. +---------+-------+---------------------------+---------------------+~~|~~Algorit~~h alg|~~JWE~~|~~XML ENC~~|~~JCA~~| |~~hm~~|orith| | |~~+---------+-------+---------------------------+---------------------+~~|~~RSA~~|~~RSA1_~~|~~http://www.w3.org/2001/04~~m|~~RSA/ECB/PKCS1Paddin~~| |~~using~~|~~5~~|~~/xmlenc#rsa-1_5~~|~~g~~RSASS|RS3|~~RSA-PKC~~http://www.w3.org/2001/04/|SHA384wi|1.2.840.113| |A|~~S1-1.5~~84|xmldsig-more#rsa-sha384|thRSA|549.1.1.12| |~~paddin~~usin| | | | |~~g~~|gSHA-| | | |~~RSA~~|~~RSA-O~~|~~http://www.w3.org/2001/04~~384|~~RSA/ECB/OAEPWithSHA~~| |~~using~~|~~AEP~~|~~/xmlenc#rsa-oaep-mgf1p~~|~~-1AndMGF1Padding~~has| |~~Optimal~~| | | |h alg|~~Asymmet~~| | | | |~~ric~~orith| | | | |~~Encryp~~|m| | | |~~tion~~| |RSASS|RS5|http://www.w3.org/2001/04/|~~Paddi~~SHA512wi|1.2.840.113| |A|12|~~ng(OAEP~~xmldsig-more#rsa-sha512|thRSA|549.1.1.13| |usin|~~)~~| | | | |~~Ellipti~~gSHA-|~~ECDH-~~|~~http://www.w3.org/2009/xm~~|~~TBD~~| |~~cCurve~~|~~ES~~512|~~lenc11#ECDH-ES~~| | |~~Diffie~~| |has| | |~~-Hellma~~| | |h alg| |~~n Ephem~~| | | |orith|~~eral~~| | | | |~~Stat~~m| | | | |~~ic~~|ECDSA|ES2|http://www.w3.org/2001/04/|SHA256wi|~~Advance~~1.2.840.100|~~A128K~~|~~http://www.w3.org/2001/04~~using|~~TBD~~56|xmldsig-more#ecdsa-sha256|~~d~~thECDSA|~~W~~45.4.3.2|~~/xmlenc#kw-aes128~~|P-256| |~~Encryp~~| | | |curve|~~tion~~| | | | |~~Stand~~and| | | | |~~ard(AES~~|SHA-2| | | |~~) Key~~| |56| | |~~Wrap~~| | | hash| | | | |~~Algo~~| algo || | | | | rithm~~R~~| | | | |~~FC 339~~|ECDSA | ES3|http://www.w3.org/2001/04/|SHA384wi|1.2.840.100|~~4 [RF~~|using|84|xmldsig-more#ecdsa-sha384|thECDSA|~~C3394]~~45.4.3.3| |P-384| | |~~using12~~| | |curve| |~~8 bitke~~| | | |and|~~ys~~| | | | |~~Advance~~SHA-3|~~A256K~~|~~http://www.w3.org/2001/04~~|~~TBD~~| |~~d~~|~~W~~84|~~/xmlenc#kw-aes256~~| | |~~Encryp~~| |hash| | |~~tion~~| | |algo| |~~Stand~~| | | |rithm|~~ard(AES~~| | | | |~~) Key~~ECDSA | ES5|http://www.w3.org/2001/04/|SHA512wi|1.2.840.100| |~~Wrap~~using|12|xmldsig-more#ecdsa-sha512|thECDSA|45.4.3.4|~~Algo~~|P-521| | | |~~rithm R~~| |curve| | |~~FC 339~~| | |and| |~~4 [RF~~| | | |SHA-5|~~C3394]~~| | | | |~~using25~~12| | | | |~~6 bitke~~|hash| | | |~~ys~~| |algo| | |~~Advance~~|~~A128C~~|~~http://www.w3.org/2001/04~~|~~AES/CBC/PKCS5Paddin~~rithm| |~~d~~|~~BC~~|~~/xmlenc#aes128-cbc~~|~~g~~+-------+-----+----------------------------+----------+-------------+ Appendix B. Encryption Algorithm Identifier Cross-Reference This appendix contains a table cross-referencing 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.REC-xmlenc-core-20021210], XML Encryption 1.1 [W3C.CR-xmlenc-core1-20120313], and Java Cryptography Architecture [JCA] for more information about the names defined by those documents. +----------+------+---------------------------+---------------------+ | Algorith|JWE|~~Encryp~~XML ENC|JCA| |m| |~~tion~~| |+----------+------+---------------------------+---------------------+|RSAES-PK|RSA1|~~Stand~~http://www.w3.org/2001/04|RSA/None/PKCS1Paddi| |CS1-V1_5|_5|~~ard(AES~~/xmlenc#rsa-1_5|ng| |RSAES|RSA-|~~) usin~~http://www.w3.org/2001/04|RSA/None/OAEPWithSH| |using|OAEP|~~g 128~~/xmlenc#rsa-oaep-mgf1p | A-1AndMGF1Padding| |Optimal| | |~~bitkeys~~| |Asymmetr| | |~~inCiph~~| |ic| | |~~er Bloc~~| |Encrypt| | |~~k Chai~~| |ion| | |~~ning(CB~~| |Paddin| | |~~C) mod~~| |g (OAEP)| | |~~e usi~~| |Elliptic|ECDH|http://www.w3.org/2009/xm|~~ng PKC~~| |Curve|-ES|lenc11#ECDH-ES|~~S #5pad~~| |Diffie-H| | |~~ding~~| |ellman| | |~~Advance~~|~~A256C~~| Ephemer | | | | | alStatic | | | | | Advanced | A128| http://www.w3.org/2001/04 |~~AES/CBC/PKCS5Paddin~~| |~~d~~Encrypti|~~BC~~KW|~~/xmlenc#aes256-cbc~~/xmlenc#kw-aes128|~~g~~| |~~Encryp~~on| | | | |~~tion~~Standar| | | | |~~Stand~~d(AES)| | | | |~~ard(AES~~Key Wra| | | | |~~) usin~~pAlgorit| | | | |~~g 256~~hmusing| | | | |~~bitkeys~~128 bi| | | | |~~inCiph~~t keys| | | | |~~er Bloc~~AES Key|A256|http://www.w3.org/2001/04| | |~~k Chai~~Wrap|KW|/xmlenc#kw-aes256| | |~~ning(CB~~Algorith| | | | |~~C) mod~~musing| | | | |~~e usi~~256 bit| | | | |~~ng PKC~~keys | | | | | AES in | A128 | http://www.w3.org/2001/04 | AES/CBC/PKCS5Paddin | | Cipher|CBC|/xmlenc#aes128-cbc|g| |~~S #5pad~~Block| | | | |~~ding~~Chaining| | | | |~~Advance~~(CBC)|~~A128G~~|~~http://www.w3.org/2009/xm~~|~~AES/GCM/NoPadding~~| |~~d~~mode|~~CM~~|~~lenc11#aes128-gcm~~| | |~~Encryp~~with| | | | |~~tion~~PKCS #5| | | | |~~Stand~~padding| | | | |~~ard(AES~~using| | | | |~~) usin~~128 bit| | | | |~~g 128~~keys| | | | |~~bitkeys~~AES in|A256|http://www.w3.org/2001/04|AES/CBC/PKCS5Paddin| |~~inGalo~~CBC mode|CBC|/xmlenc#aes256-cbc|g| |~~is/Coun~~with| | | | |~~ter Mod~~PKCS #5| | | | |~~e (GC~~padding| | | | |~~M)~~using| | | | |~~Advance~~256 bit|~~A256G~~|~~http://www.w3.org/2009/xm~~|~~AES/GCM/NoPadding~~| |~~d~~keys|~~CM~~|~~lenc11#aes256-gcm~~| | |~~Encryp~~AES in|A128|http://www.w3.org/2009/xm|AES/GCM/NoPadding| |~~tion~~Galois/C|GCM|lenc11#aes128-gcm| | |~~Stand~~ounter| | | | |~~ard(AES~~Mode| | | | |~~) usin~~(GCM)| | | | |~~g 256~~using| | | | |~~bitkeys~~128 bit| | | | |~~inGalo~~keys| | | | |~~is/Coun~~AES GCM|A256|http://www.w3.org/2009/xm|AES/GCM/NoPadding| |~~ter Mod~~using|GCM|lenc11#aes256-gcm| | |~~e (GC~~256 bit| | | | |~~M)~~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 [I-D.rescorla-jsms], 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 SHA-256 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 UTF-8 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. 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 o Moved definition of "alg":"none" for JWSs here from the JWT specification since this functionality is likely to be useful in more contexts that just for JWTs. o Added Advanced Encryption Standard (AES) Key Wrap Algorithm using 512 bit keys ("A512KW"). o Added text "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". o Corrected the Magic Signatures reference. o Made other editorial improvements suggested by JOSE working group participants. -00 o Created the initial IETF draft based upon draft-jones-json-web-signature-04 and draft-jones-json-web-encryption-02 with no normative changes. o Changed terminology to no longer call both digital signatures and HMACs "signatures". Author's Address Michael B. Jones Microsoft Email: mbj@microsoft.com URI: http://self-issued.info/