JOSE Working Group M. Jones Internet-Draft Microsoft Intended status: Standards Track E. Rescorla Expires: June 30, 2013 RTFM J. Hildebrand Cisco December 27, 2012 JSON Web Encryption (JWE) draft-ietf-jose-json-web-encryption-08 Abstract JSON Web Encryption (JWE) is a means of representing encrypted content using JavaScript Object Notation (JSON) data structures. Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) specification. Related digital signature and MAC capabilities are described in the separate JSON Web Signature (JWS) specification. 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 June 30, 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 Jones, et al. Expires June 30, 2013 [Page 1] Internet-Draft JWE December 2012 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 . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 3. JSON Web Encryption (JWE) Overview . . . . . . . . . . . . . . 7 3.1. Example JWE using RSAES OAEP and AES GCM . . . . . . . . . 8 3.2. Example JWE using RSAES-PKCS1-V1_5 and AES CBC . . . . . . 9 4. JWE Header . . . . . . . . . . . . . . . . . . . . . . . . . . 11 4.1. Reserved Header Parameter Names . . . . . . . . . . . . . 12 4.1.1. "alg" (Algorithm) Header Parameter . . . . . . . . . . 12 4.1.2. "enc" (Encryption Method) Header Parameter . . . . . . 12 4.1.3. "epk" (Ephemeral Public Key) Header Parameter . . . . 13 4.1.4. "zip" (Compression Algorithm) Header Parameter . . . . 13 4.1.5. "jku" (JWK Set URL) Header Parameter . . . . . . . . . 13 4.1.6. "jwk" (JSON Web Key) Header Parameter . . . . . . . . 13 4.1.7. "x5u" (X.509 URL) Header Parameter . . . . . . . . . . 13 4.1.8. "x5t" (X.509 Certificate Thumbprint) Header Parameter . . . . . . . . . . . . . . . . . . . . . . 14 4.1.9. "x5c" (X.509 Certificate Chain) Header Parameter . . . 14 4.1.10. "kid" (Key ID) Header Parameter . . . . . . . . . . . 15 4.1.11. "typ" (Type) Header Parameter . . . . . . . . . . . . 15 4.1.12. "cty" (Content Type) Header Parameter . . . . . . . . 15 4.1.13. "apu" (Agreement PartyUInfo) Header Parameter . . . . 15 4.1.14. "apv" (Agreement PartyVInfo) Header Parameter . . . . 15 4.1.15. "epu" (Encryption PartyUInfo) Header Parameter . . . . 16 4.1.16. "epv" (Encryption PartyVInfo) Header Parameter . . . . 16 4.2. Public Header Parameter Names . . . . . . . . . . . . . . 16 4.3. Private Header Parameter Names . . . . . . . . . . . . . . 16 5. Producing and Consuming JWEs . . . . . . . . . . . . . . . . . 16 5.1. Message Encryption . . . . . . . . . . . . . . . . . . . . 16 5.2. Message Decryption . . . . . . . . . . . . . . . . . . . . 18 5.3. String Comparison Rules . . . . . . . . . . . . . . . . . 19 6. Encrypting JWEs with Cryptographic Algorithms . . . . . . . . 20 6.1. CMK Encryption . . . . . . . . . . . . . . . . . . . . . . 20 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20 7.1. Registration of JWE Header Parameter Names . . . . . . . . 20 7.1.1. Registry Contents . . . . . . . . . . . . . . . . . . 21 7.2. JSON Web Signature and Encryption Type Values Registration . . . . . . . . . . . . . . . . . . . . . . . 22 7.2.1. Registry Contents . . . . . . . . . . . . . . . . . . 22 7.3. Media Type Registration . . . . . . . . . . . . . . . . . 23 Jones, et al. Expires June 30, 2013 [Page 2] Internet-Draft JWE December 2012 7.3.1. Registry Contents . . . . . . . . . . . . . . . . . . 23 8. Security Considerations . . . . . . . . . . . . . . . . . . . 23 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 24 9.1. Normative References . . . . . . . . . . . . . . . . . . . 24 9.2. Informative References . . . . . . . . . . . . . . . . . . 25 Appendix A. JWE Examples . . . . . . . . . . . . . . . . . . . . 25 A.1. Example JWE using RSAES OAEP and AES GCM . . . . . . . . . 26 A.1.1. JWE Header . . . . . . . . . . . . . . . . . . . . . . 26 A.1.2. Encoded JWE Header . . . . . . . . . . . . . . . . . . 26 A.1.3. Content Master Key (CMK) . . . . . . . . . . . . . . . 26 A.1.4. Key Encryption . . . . . . . . . . . . . . . . . . . . 26 A.1.5. Encoded JWE Encrypted Key . . . . . . . . . . . . . . 29 A.1.6. Initialization Vector . . . . . . . . . . . . . . . . 29 A.1.7. "Additional Authenticated Data" Parameter . . . . . . 29 A.1.8. Plaintext Encryption . . . . . . . . . . . . . . . . . 30 A.1.9. Encoded JWE Ciphertext . . . . . . . . . . . . . . . . 30 A.1.10. Encoded JWE Integrity Value . . . . . . . . . . . . . 31 A.1.11. Complete Representation . . . . . . . . . . . . . . . 31 A.1.12. Validation . . . . . . . . . . . . . . . . . . . . . . 31 A.2. Example JWE using RSAES-PKCS1-V1_5 and AES CBC . . . . . . 31 A.2.1. JWE Header . . . . . . . . . . . . . . . . . . . . . . 32 A.2.2. Encoded JWE Header . . . . . . . . . . . . . . . . . . 32 A.2.3. Content Master Key (CMK) . . . . . . . . . . . . . . . 32 A.2.4. Key Encryption . . . . . . . . . . . . . . . . . . . . 32 A.2.5. Encoded JWE Encrypted Key . . . . . . . . . . . . . . 35 A.2.6. Key Derivation . . . . . . . . . . . . . . . . . . . . 35 A.2.7. Initialization Vector . . . . . . . . . . . . . . . . 35 A.2.8. Plaintext Encryption . . . . . . . . . . . . . . . . . 35 A.2.9. Encoded JWE Ciphertext . . . . . . . . . . . . . . . . 36 A.2.10. Secured Input Value . . . . . . . . . . . . . . . . . 36 A.2.11. JWE Integrity Value . . . . . . . . . . . . . . . . . 37 A.2.12. Encoded JWE Integrity Value . . . . . . . . . . . . . 37 A.2.13. Complete Representation . . . . . . . . . . . . . . . 37 A.2.14. Validation . . . . . . . . . . . . . . . . . . . . . . 38 A.3. Example JWE using AES Key Wrap and AES GCM . . . . . . . . 38 A.3.1. JWE Header . . . . . . . . . . . . . . . . . . . . . . 38 A.3.2. Encoded JWE Header . . . . . . . . . . . . . . . . . . 39 A.3.3. Content Master Key (CMK) . . . . . . . . . . . . . . . 39 A.3.4. Key Encryption . . . . . . . . . . . . . . . . . . . . 39 A.3.5. Encoded JWE Encrypted Key . . . . . . . . . . . . . . 39 A.3.6. Initialization Vector . . . . . . . . . . . . . . . . 39 A.3.7. "Additional Authenticated Data" Parameter . . . . . . 40 A.3.8. Plaintext Encryption . . . . . . . . . . . . . . . . . 40 A.3.9. Encoded JWE Ciphertext . . . . . . . . . . . . . . . . 40 A.3.10. Encoded JWE Integrity Value . . . . . . . . . . . . . 41 A.3.11. Complete Representation . . . . . . . . . . . . . . . 41 A.3.12. Validation . . . . . . . . . . . . . . . . . . . . . . 41 A.4. Example Key Derivation for "enc" value "A128CBC+HS256" . . 41 Jones, et al. Expires June 30, 2013 [Page 3] Internet-Draft JWE December 2012 A.4.1. CEK Generation . . . . . . . . . . . . . . . . . . . . 42 A.4.2. CIK Generation . . . . . . . . . . . . . . . . . . . . 43 A.5. Example Key Derivation for "enc" value "A256CBC+HS512" . . 44 A.5.1. CEK Generation . . . . . . . . . . . . . . . . . . . . 44 A.5.2. CIK Generation . . . . . . . . . . . . . . . . . . . . 45 Appendix B. Acknowledgements . . . . . . . . . . . . . . . . . . 46 Appendix C. Open Issues . . . . . . . . . . . . . . . . . . . . . 47 Appendix D. Document History . . . . . . . . . . . . . . . . . . 47 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 51 Jones, et al. Expires June 30, 2013 [Page 4] Internet-Draft JWE December 2012 1. Introduction JSON Web Encryption (JWE) is a compact encryption format intended for space constrained environments such as HTTP Authorization headers and URI query parameters. It represents this content using JavaScript Object Notation (JSON) [RFC4627] based data structures. The JWE cryptographic mechanisms encrypt and provide integrity protection for arbitrary sequences of bytes. Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) [JWA] specification. Related digital signature and MAC capabilities are described in the separate JSON Web Signature (JWS) [JWS] specification. 1.1. Notational Conventions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in Key words for use in RFCs to Indicate Requirement Levels [RFC2119]. 2. Terminology JSON Web Encryption (JWE) A data structure representing an encrypted message. The structure consists of five parts: the JWE Header, the JWE Encrypted Key, the JWE Initialization Vector, the JWE Ciphertext, and the JWE Integrity Value. Plaintext The bytes to be encrypted -- a.k.a., the message. The plaintext can contain an arbitrary sequence of bytes. Ciphertext An encrypted representation of the Plaintext. Content Encryption Key (CEK) A symmetric key used to encrypt the Plaintext for the recipient to produce the Ciphertext. Content Integrity Key (CIK) A key used with a MAC function to ensure the integrity of the Ciphertext and the parameters used to create it. Content Master Key (CMK) A key from which the CEK and CIK are derived. When key wrapping or key encryption are employed, the CMK is randomly generated and encrypted to the recipient as the JWE Encrypted Key. When direct encryption with a shared symmetric key is employed, the CMK is the shared key. When key agreement without key wrapping is employed, the CMK is the result of the key Jones, et al. Expires June 30, 2013 [Page 5] Internet-Draft JWE December 2012 agreement algorithm. JSON Text Object A UTF-8 encoded text string representing a JSON object; the syntax of JSON objects is defined in Section 2.2 of [RFC4627]. JWE Header A JSON Text Object that describes the encryption operations applied to create the JWE Encrypted Key, the JWE Ciphertext, and the JWE Integrity Value. JWE Encrypted Key When key wrapping or key encryption are employed, the Content Master Key (CMK) is encrypted with the intended recipient's key and the resulting encrypted content is recorded as a byte array, which is referred to as the JWE Encrypted Key. Otherwise, when direct encryption with a shared or agreed upon symmetric key is employed, the JWE Encrypted Key is the empty byte array. JWE Initialization Vector A byte array containing the Initialization Vector used when encrypting the Plaintext. JWE Ciphertext A byte array containing the Ciphertext. JWE Integrity Value A byte array containing a MAC value that ensures the integrity of the Ciphertext and the parameters used to create it. Base64url Encoding The URL- and filename-safe Base64 encoding described in RFC 4648 [RFC4648], Section 5, with the (non URL- safe) '=' padding characters omitted, as permitted by Section 3.2. (See Appendix C of [JWS] for notes on implementing base64url encoding without padding.) Encoded JWE Header Base64url encoding of the JWE Header. Encoded JWE Encrypted Key Base64url encoding of the JWE Encrypted Key. Encoded JWE Initialization Vector Base64url encoding of the JWE Initialization Vector. Encoded JWE Ciphertext Base64url encoding of the JWE Ciphertext. Encoded JWE Integrity Value Base64url encoding of the JWE Integrity Value. Jones, et al. Expires June 30, 2013 [Page 6] Internet-Draft JWE December 2012 Header Parameter Name The name of a member of the JWE Header. Header Parameter Value The value of a member of the JWE Header. JWE Compact Serialization A representation of the JWE as the concatenation of the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value in that order, with the five strings being separated by four period ('.') characters. Authenticated Encryption An Authenticated Encryption algorithm is one that provides an integrated content integrity check. Authenticated Encryption algorithms accept two inputs, the plaintext and the "additional authenticated data" value, and produce two outputs, the ciphertext and the "authentication tag" value. AES Galois/Counter Mode (GCM) is one such algorithm. Collision Resistant Namespace A namespace that allows names to be allocated in a manner such that they are highly unlikely to collide with other names. For instance, collision resistance can be achieved through administrative delegation of portions of the namespace or through use of 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]. When using an administratively delegated namespace, the definer of a name needs to take reasonable precautions to ensure they are in control of the portion of the namespace they use to define the name. StringOrURI A JSON string value, with the additional requirement that while arbitrary string values MAY be used, any value containing a ":" character MUST be a URI [RFC3986]. StringOrURI values are compared as case-sensitive strings with no transformations or canonicalizations applied. 3. JSON Web Encryption (JWE) Overview JWE represents encrypted content using JSON data structures and base64url encoding. The representation consists of five parts: the JWE Header, the JWE Encrypted Key, the JWE Initialization Vector, the JWE Ciphertext, and the JWE Integrity Value. In the Compact Serialization, the five parts are base64url-encoded for transmission, and represented as the concatenation of the encoded strings in that order, with the five strings being separated by four period ('.') characters. (A JSON Serialization for this information is defined in Jones, et al. Expires June 30, 2013 [Page 7] Internet-Draft JWE December 2012 the separate JSON Web Encryption JSON Serialization (JWE-JS) [JWE-JS] specification.) JWE utilizes encryption to ensure the confidentiality of the Plaintext. JWE adds a content integrity check if not provided by the underlying encryption algorithm. 3.1. Example JWE using RSAES OAEP and AES GCM This example encrypts the plaintext "Live long and prosper." to the recipient using RSAES OAEP and AES GCM. The AES GCM algorithm has an integrated integrity check. The following example JWE Header declares that: o the Content Master Key is encrypted to the recipient using the RSAES OAEP algorithm to produce the JWE Encrypted Key and o the Plaintext is encrypted using the AES GCM algorithm with a 256 bit key to produce the Ciphertext. {"alg":"RSA-OAEP","enc":"A256GCM"} Base64url encoding the bytes of the UTF-8 representation of the JWE Header yields this Encoded JWE Header value: eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ The remaining steps to finish creating this JWE are: o Generate a random Content Master Key (CMK) o Encrypt the CMK with the recipient's public key using the RSAES OAEP algorithm to produce the JWE Encrypted Key o Base64url encode the JWE Encrypted Key to produce the Encoded JWE Encrypted Key o Generate a random JWE Initialization Vector o Base64url encode the JWE Initialization Vector to produce the Encoded JWE Initialization Vector o Concatenate the Encoded JWE Header value, a period character ('.'), the Encoded JWE Encrypted Key, a second period character ('.'), and the Encoded JWE Initialization Vector to create the "additional authenticated data" parameter for the AES GCM Jones, et al. Expires June 30, 2013 [Page 8] Internet-Draft JWE December 2012 algorithm o Encrypt the Plaintext with AES GCM, using the CMK as the encryption key, the JWE Initialization Vector, and the "additional authenticated data" value above, requesting a 128 bit "authentication tag" output o Base64url encode the resulting Ciphertext to create the Encoded JWE Ciphertext o Base64url encode the resulting "authentication tag" to create the Encoded JWE Integrity Value o Assemble the final representation: The Compact Serialization of this result is the concatenation of the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value in that order, with the five strings being separated by four period ('.') characters. The final result in this example (with line breaks for display purposes only) is: eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ. M2XxpbORKezKSzzQL_95-GjiudRBTqn_omS8z9xgoRb7L0Jw5UsEbxmtyHn2T71m rZLkjg4Mp8gbhYoltPkEOHvAopz25-vZ8C2e1cOaAo5WPcbSIuFcB4DjBOM3t0UA O6JHkWLuAEYoe58lcxIQneyKdaYSLbV9cKqoUoFQpvKWYRHZbfszIyfsa18rmgTj zrtLDTPnc09DSJE24aQ8w3i8RXEDthW9T1J6LsTH_vwHdwUgkI-tC2PNeGrnM-dN SfzF3Y7-lwcGy0FsdXkPXytvDV7y4pZeeUiQ-0VdibIN2AjjfW60nfrPuOjepMFG 6BBBbR37pHcyzext9epOAQ. 48V1_ALb6US04U3b. _e21tGGhac_peEFkLXr2dMPUZiUkrw. 7V5ZDko0v_mf2PAc4JMiUg See Appendix A.1 for the complete details of computing this JWE. 3.2. Example JWE using RSAES-PKCS1-V1_5 and AES CBC This example encrypts the plaintext "No matter where you go, there you are." to the recipient using RSAES-PKCS1-V1_5 and AES CBC. AES CBC does not have an integrated integrity check, so a separate integrity check calculation is performed using HMAC SHA-256, with separate encryption and integrity keys being derived from a master key using the Concat KDF with the SHA-256 digest function. The following example JWE Header (with line breaks for display purposes only) declares that: Jones, et al. Expires June 30, 2013 [Page 9] Internet-Draft JWE December 2012 o the Content Master Key is encrypted to the recipient using the RSAES-PKCS1-V1_5 algorithm to produce the JWE Encrypted Key and o the Plaintext is encrypted using the AES CBC algorithm with a 128 bit key to produce the Ciphertext, with the integrity of the Ciphertext and the parameters used to create it being secured using the HMAC SHA-256 algorithm. {"alg":"RSA1_5","enc":"A128CBC+HS256"} Base64url encoding the bytes of the UTF-8 representation of the JWE Header yields this Encoded JWE Header value: eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDK0hTMjU2In0 The remaining steps to finish creating this JWE are like the previous example, but with an additional step to compute the separate integrity value: o Generate a random Content Master Key (CMK) o Encrypt the CMK with the recipient's public key using the RSAES- PKCS1-V1_5 algorithm to produce the JWE Encrypted Key o Base64url encode the JWE Encrypted Key to produce the Encoded JWE Encrypted Key o Generate a random JWE Initialization Vector o Base64url encode the JWE Initialization Vector to produce the Encoded JWE Initialization Vector o Use the Concat key derivation function to derive Content Encryption Key (CEK) and Content Integrity Key (CIK) values from the CMK o Encrypt the Plaintext with AES CBC using the CEK and JWE Initialization Vector to produce the Ciphertext o Base64url encode the resulting Ciphertext to create the Encoded JWE Ciphertext o Concatenate the Encoded JWE Header value, a period character ('.'), the Encoded JWE Encrypted Key, a second period character ('.'), the Encoded JWE Initialization Vector, a third period ('.') character, and the Encoded JWE Ciphertext to create the value to integrity protect Jones, et al. Expires June 30, 2013 [Page 10] Internet-Draft JWE December 2012 o Compute the HMAC SHA-256 of this value using the CIK to create the JWE Integrity Value o Base64url encode the resulting JWE Integrity Value to create the Encoded JWE Integrity Value o Assemble the final representation: The Compact Serialization of this result is the concatenation of the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value in that order, with the five strings being separated by four period ('.') characters. The final result in this example (with line breaks for display purposes only) is: eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDK0hTMjU2In0. O6AqXqgVlJJ4c4lp5sXZd7bpGHAw6ARkHUeXQxD1cAW4-X1x0qtj_AN0mukqEOl4 Y6UOwJXIJY9-G1ELK-RQWrKH_StR-AM9H7GpKmSEji8QYOcMOjr-u9H1Lt_pBEie G802SxWz0rbFTXRcj4BWLxcpCtjUZ31AP-sc-L_eCZ5UNl0aSRNqFskuPkzRsFZR DJqSSJeVOyJ7pZCQ83fli19Vgi_3R7XMUqluQuuc7ZHOWixi47jXlBTlWRZ5iFxa S8G6J8wUrd4BKggAw3qX5XoIfXQVlQZE0Vmkq_zQSIo5LnFKyowooRcdsEuNh9B9 Mkyt0ZQElG-jGdtHWjZSOA. AxY8DCtDaGlsbGljb3RoZQ. 1eBWFgcrz40wC88cgv8rPgu3EfmC1p4zT0kIxxfSF2zDJcQ-iEHk1jQM95xAdr5Z. RBGhYzE8_cZLHjJqqHuLhzbgWgL_wV3LDSUrcbkOiIA See Appendix A.2 for the complete details of computing this JWE. 4. JWE Header The members of the JSON object represented by the JWE Header describe the encryption applied to the Plaintext and optionally additional properties of the JWE. The Header Parameter Names within this object MUST be unique; JWEs with duplicate Header Parameter Names MUST be rejected. Implementations MUST understand the entire contents of the header; otherwise, the JWE MUST be rejected. There are two ways of distinguishing whether a header is a JWS Header or a JWE Header. The first is by examining the "alg" (algorithm) header value. If the value represents a digital signature or MAC algorithm, or is the value "none", it is for a JWS; if it represents an encryption or key agreement algorithm, it is for a JWE. A second method is determining whether an "enc" (encryption method) member exists. If the "enc" member exists, it is a JWE; otherwise, it is a JWS. Both methods will yield the same result for all legal input values. Jones, et al. Expires June 30, 2013 [Page 11] Internet-Draft JWE December 2012 There are three classes of Header Parameter Names: Reserved Header Parameter Names, Public Header Parameter Names, and Private Header Parameter Names. 4.1. Reserved Header Parameter Names The following Header Parameter Names are reserved with meanings as defined below. All the names are short because a core goal of JWE is for the representations to be compact. 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. 4.1.1. "alg" (Algorithm) Header Parameter The "alg" (algorithm) header parameter identifies the cryptographic algorithm used to encrypt or determine the value of the Content Master Key (CMK). The algorithm specified by the "alg" value MUST be supported by the implementation and there MUST be a key for use with that algorithm associated with the intended recipient or the JWE MUST be rejected. "alg" values SHOULD either be registered in the IANA JSON Web Signature and Encryption Algorithms registry [JWA] or be a value that contains a Collision Resistant Namespace. The "alg" value is a case sensitive string containing a StringOrURI value. Use of this header parameter is REQUIRED. A list of defined "alg" values can be found in the IANA JSON Web Signature and Encryption Algorithms registry [JWA]; the initial contents of this registry are the values defined in Section 4.1 of the JSON Web Algorithms (JWA) [JWA] specification. 4.1.2. "enc" (Encryption Method) Header Parameter The "enc" (encryption method) header parameter identifies the block encryption algorithm used to encrypt the Plaintext to produce the Ciphertext. This algorithm MUST be an Authenticated Encryption algorithm with a specified key length. The algorithm specified by the "enc" value MUST be supported by the implementation or the JWE MUST be rejected. "enc" values SHOULD either be registered in the IANA JSON Web Signature and Encryption Algorithms registry [JWA] or be a value that contains a Collision Resistant Namespace. The "enc" value is a case sensitive string containing a StringOrURI value. Use of this header parameter is REQUIRED. Jones, et al. Expires June 30, 2013 [Page 12] Internet-Draft JWE December 2012 A list of defined "enc" values can be found in the IANA JSON Web Signature and Encryption Algorithms registry [JWA]; the initial contents of this registry are the values defined in Section 4.2 of the JSON Web Algorithms (JWA) [JWA] specification. 4.1.3. "epk" (Ephemeral Public Key) Header Parameter The "epk" (ephemeral public key) value created by the originator for the use in key agreement algorithms. This key is represented as a JSON Web Key [JWK] value. Use of this header parameter is OPTIONAL, although its use is REQUIRED with some "alg" algorithms. 4.1.4. "zip" (Compression Algorithm) Header Parameter The "zip" (compression algorithm) applied to the Plaintext before encryption, if any. If present, the value of the "zip" header parameter MUST be the case sensitive string "DEF". Compression is performed with the DEFLATE [RFC1951] algorithm. If no "zip" parameter is present, no compression is applied to the Plaintext before encryption. Use of this header parameter is OPTIONAL. 4.1.5. "jku" (JWK Set URL) Header Parameter The "jku" (JWK Set URL) header parameter is a URI [RFC3986] that refers to a resource for a set of JSON-encoded public keys, one of which corresponds to the key used to encrypt the JWE; this can be used to determine the private key needed to decrypt the JWE. The keys MUST be encoded as a JSON Web Key Set (JWK Set) [JWK]. The protocol used to acquire the resource MUST provide integrity protection; an HTTP GET request to retrieve the certificate MUST use TLS [RFC2818] [RFC5246]; the identity of the server MUST be validated, as per Section 3.1 of HTTP Over TLS [RFC2818]. Use of this header parameter is OPTIONAL. 4.1.6. "jwk" (JSON Web Key) Header Parameter The "jwk" (JSON Web Key) header parameter is a public key that corresponds to the key used to encrypt the JWE; this can be used to determine the private key needed to decrypt the JWE. This key is represented as a JSON Web Key [JWK]. Use of this header parameter is OPTIONAL. 4.1.7. "x5u" (X.509 URL) Header Parameter The "x5u" (X.509 URL) header parameter is a URI [RFC3986] that refers to a resource for the X.509 public key certificate or certificate chain [RFC5280] corresponding to the key used to encrypt the JWE; this can be used to determine the private key needed to decrypt the Jones, et al. Expires June 30, 2013 [Page 13] Internet-Draft JWE December 2012 JWE. The identified resource MUST provide a representation of the certificate or certificate chain that conforms to RFC 5280 [RFC5280] in PEM encoded form [RFC1421]. The certificate containing the public key of the entity that encrypted the JWE MUST be the first certificate. This MAY be followed by additional certificates, with each subsequent certificate being the one used to certify the previous one. The protocol used to acquire the resource MUST provide integrity protection; an HTTP GET request to retrieve the certificate MUST use TLS [RFC2818] [RFC5246]; the identity of the server MUST be validated, as per Section 3.1 of HTTP Over TLS [RFC2818]. Use of this header parameter is OPTIONAL. 4.1.8. "x5t" (X.509 Certificate Thumbprint) Header Parameter The "x5t" (X.509 Certificate Thumbprint) header parameter provides a base64url encoded SHA-1 thumbprint (a.k.a. digest) of the DER encoding of the X.509 certificate [RFC5280] corresponding to the key used to encrypt the JWE; this can be used to determine the private key needed to decrypt the JWE. Use of this header parameter is OPTIONAL. If, in the future, certificate thumbprints need to be computed using hash functions other than SHA-1, it is suggested that additional related header parameters be defined for that purpose. For example, it is suggested that a new "x5t#S256" (X.509 Certificate Thumbprint using SHA-256) header parameter could be defined by registering it in the IANA JSON Web Signature and Encryption Header Parameters registry [JWS]. 4.1.9. "x5c" (X.509 Certificate Chain) Header Parameter The "x5c" (X.509 Certificate Chain) header parameter contains the X.509 public key certificate or certificate chain [RFC5280] corresponding to the key used to encrypt the JWE; this can be used to determine the private key needed to decrypt the JWE. The certificate or certificate chain is represented as an array of certificate value strings. Each string is a base64 encoded ([RFC4648] Section 4 -- not base64url encoded) DER [ITU.X690.1994] PKIX certificate value. The certificate containing the public key of the entity that encrypted the JWE MUST be the first certificate. This MAY be followed by additional certificates, with each subsequent certificate being the one used to certify the previous one. The recipient MUST verify the certificate chain according to [RFC5280] and reject the JWE if any validation failure occurs. Use of this header parameter is OPTIONAL. See Appendix B of [JWS] for an example "x5c" value. Jones, et al. Expires June 30, 2013 [Page 14] Internet-Draft JWE December 2012 4.1.10. "kid" (Key ID) Header Parameter The "kid" (key ID) header parameter is a hint indicating which key was used to encrypt the JWE; this can be used to determine the private key needed to decrypt the JWE. This parameter allows originators to explicitly signal a change of key to recipients. Should the recipient be unable to locate a key corresponding to the "kid" value, they SHOULD treat that condition as an error. The interpretation of the "kid" value is unspecified. Its value MUST be a string. Use of this header parameter is OPTIONAL. When used with a JWK, the "kid" value MAY be used to match a JWK "kid" parameter value. 4.1.11. "typ" (Type) Header Parameter The "typ" (type) header parameter is used to declare the type of this object. The type value "JWE" MAY be used to indicate that this object is a JWE. The "typ" value is a case sensitive string. Use of this header parameter is OPTIONAL. MIME Media Type [RFC2046] values MAY be used as "typ" values. "typ" values SHOULD either be registered in the IANA JSON Web Signature and Encryption Type Values registry [JWS] or be a value that contains a Collision Resistant Namespace. 4.1.12. "cty" (Content Type) Header Parameter The "cty" (content type) header parameter is used to declare the type of the encrypted content (the Plaintext). The "cty" value is a case sensitive string. Use of this header parameter is OPTIONAL. The values used for the "cty" header parameter come from the same value space as the "typ" header parameter, with the same rules applying. 4.1.13. "apu" (Agreement PartyUInfo) Header Parameter The "apu" (agreement PartyUInfo) value for key agreement algorithms using it (such as "ECDH-ES"), represented as a base64url encoded string. Use of this header parameter is OPTIONAL. 4.1.14. "apv" (Agreement PartyVInfo) Header Parameter The "apv" (agreement PartyVInfo) value for key agreement algorithms using it (such as "ECDH-ES"), represented as a base64url encoded string. Use of this header parameter is OPTIONAL. Jones, et al. Expires June 30, 2013 [Page 15] Internet-Draft JWE December 2012 4.1.15. "epu" (Encryption PartyUInfo) Header Parameter The "epu" (encryption PartyUInfo) value for plaintext encryption algorithms using it (such as "A128CBC+HS256"), represented as a base64url encoded string. Use of this header parameter is OPTIONAL. 4.1.16. "epv" (Encryption PartyVInfo) Header Parameter The "epv" (encryption PartyVInfo) value for plaintext encryption algorithms using it (such as "A128CBC+HS256"), represented as a base64url encoded string. Use of this header parameter is OPTIONAL. 4.2. Public Header Parameter Names Additional Header Parameter Names can be defined by those using JWEs. However, in order to prevent collisions, any new Header Parameter Name SHOULD either be registered in the IANA JSON Web Signature and Encryption Header Parameters registry [JWS] or be a Public Name: a value that contains a Collision Resistant Namespace. In each case, the definer of the name or value needs to take reasonable precautions to make sure they are in control of the part of the namespace they use to define the Header Parameter Name. New header parameters should be introduced sparingly, as they can result in non-interoperable JWEs. 4.3. Private Header Parameter Names A producer and consumer of a JWE may agree to use Header Parameter Names that are Private Names: names that are not Reserved Names Section 4.1 or Public Names Section 4.2. Unlike Public Names, Private Names are subject to collision and should be used with caution. 5. Producing and Consuming JWEs 5.1. Message Encryption The message encryption process is as follows. The order of the steps is not significant in cases where there are no dependencies between the inputs and outputs of the steps. 1. When key wrapping, key encryption, or key agreement with key wrapping are employed, generate a random Content Master Key (CMK). See RFC 4086 [RFC4086] for considerations on generating random values. The CMK MUST have a length equal to that required for the block encryption algorithm. Jones, et al. Expires June 30, 2013 [Page 16] Internet-Draft JWE December 2012 2. When key agreement is employed, use the key agreement algorithm to compute the value of the agreed upon key. When key agreement without key wrapping is employed, let the Content Master Key (CMK) be the agreed upon key. When key agreement with key wrapping is employed, the agreed upon key will be used to wrap the CMK. 3. When key wrapping, key encryption, or key agreement with key wrapping are employed, encrypt the CMK for the recipient (see Section 6.1) and let the result be the JWE Encrypted Key. Otherwise, when direct encryption with a shared or agreed upon symmetric key is employed, let the JWE Encrypted Key be the empty byte array. 4. When direct encryption with a shared symmetric key is employed, let the Content Master Key (CMK) be the shared key. 5. Base64url encode the JWE Encrypted Key to create the Encoded JWE Encrypted Key. 6. Generate a random JWE Initialization Vector of the correct size for the block encryption algorithm (if required for the algorithm); otherwise, let the JWE Initialization Vector be the empty byte string. 7. Base64url encode the JWE Initialization Vector to create the Encoded JWE Initialization Vector. 8. Compress the Plaintext if a "zip" parameter was included. 9. Serialize the (compressed) Plaintext into a byte sequence M. 10. Create a JWE Header containing the encryption parameters used. Note that white space is explicitly allowed in the representation and no canonicalization need be performed before encoding. 11. Base64url encode the bytes of the UTF-8 representation of the JWE Header to create the Encoded JWE Header. 12. Let the "additional authenticated data" value be the bytes of the ASCII representation of the concatenation of the Encoded JWE Header, a period ('.') character, the Encoded JWE Encrypted Key, a second period character ('.'), and the Encoded JWE Initialization Vector. 13. Encrypt M using the CMK, the JWE Initialization Vector, and the "additional authenticated data" value using the specified block Jones, et al. Expires June 30, 2013 [Page 17] Internet-Draft JWE December 2012 encryption algorithm to create the JWE Ciphertext value and the JWE Integrity Value (which is the "authentication tag" output from the calculation). 14. Base64url encode the JWE Ciphertext to create the Encoded JWE Ciphertext. 15. Base64url encode the JWE Integrity Value to create the Encoded JWE Integrity Value. 16. The five encoded parts, taken together, are the result. 17. The Compact Serialization of this result is the concatenation of the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value in that order, with the five strings being separated by four period ('.') characters. 5.2. Message Decryption The message decryption process is the reverse of the encryption process. The order of the steps is not significant in cases where there are no dependencies between the inputs and outputs of the steps. If any of these steps fails, the JWE MUST be rejected. 1. Determine the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value values contained in the JWE. When using the Compact Serialization, these five values are represented in that order, separated by four period ('.') characters. 2. The Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value MUST be successfully base64url decoded following the restriction that no padding characters have been used. 3. The resulting JWE Header MUST be completely valid JSON syntax conforming to RFC 4627 [RFC4627]. 4. The resulting JWE Header MUST be validated to only include parameters and values whose syntax and semantics are both understood and supported. 5. Verify that the JWE uses a key known to the recipient. Jones, et al. Expires June 30, 2013 [Page 18] Internet-Draft JWE December 2012 6. When key agreement is employed, use the key agreement algorithm to compute the value of the agreed upon key. When key agreement without key wrapping is employed, let the Content Master Key (CMK) be the agreed upon key. When key agreement with key wrapping is employed, the agreed upon key will be used to decrypt the JWE Encrypted Key. 7. When key wrapping, key encryption, or key agreement with key wrapping are employed, decrypt the JWE Encrypted Key to produce the Content Master Key (CMK). The CMK MUST have a length equal to that required for the block encryption algorithm. 8. When direct encryption with a shared symmetric key is employed, let the Content Master Key (CMK) be the shared key. 9. Let the "additional authenticated data" value be the bytes of the ASCII representation of the concatenation of the Encoded JWE Header, a period ('.') character, the Encoded JWE Encrypted Key, a second period character ('.'), and the Encoded JWE Initialization Vector. 10. Decrypt the JWE Ciphertext using the CMK, the JWE Initialization Vector, the "additional authenticated data" value, and the JWE Integrity Value (which is the "authentication tag" input to the calculation) using the specified block encryption algorithm, returning the decrypted plaintext and verifying the JWE Integrity Value in the manner specified for the algorithm, rejecting the input without emitting any decrypted output if the JWE Integrity Value is incorrect. 11. Uncompress the decrypted plaintext if a "zip" parameter was included. 12. Output the resulting Plaintext. 5.3. String Comparison Rules Processing a JWE inevitably requires comparing known strings to values in JSON objects. For example, in checking what the encryption method is, the Unicode string encoding "enc" will be checked against the member names in the JWE Header to see if there is a matching Header Parameter Name. Comparisons between JSON strings and other Unicode strings MUST be performed by comparing Unicode code points without normalization as specified in the String Comparison Rules in Section 5.3 of [JWS]. Jones, et al. Expires June 30, 2013 [Page 19] Internet-Draft JWE December 2012 6. Encrypting JWEs with Cryptographic Algorithms JWE uses cryptographic algorithms to encrypt the Plaintext and the Content Encryption Key (CMK) and to provide integrity protection for the JWE Header, JWE Encrypted Key, and JWE Ciphertext. The JSON Web Algorithms (JWA) [JWA] specification specifies a set of cryptographic algorithms and identifiers to be used with this specification and defines registries for additional such algorithms. Specifically, Section 4.1 specifies a set of "alg" (algorithm) header parameter values and Section 4.2 specifies a set of "enc" (encryption method) header parameter values intended for use this specification. It also describes the semantics and operations that are specific to these algorithms. Public keys employed for encryption can be identified using the Header Parameter methods described in Section 4.1 or can be distributed using methods that are outside the scope of this specification. 6.1. CMK Encryption JWE supports three forms of Content Master Key (CMK) encryption: o Asymmetric encryption under the recipient's public key. o Symmetric encryption under a key shared between the sender and receiver. o Symmetric encryption under a key agreed upon between the sender and receiver. See the algorithms registered for "enc" usage in the IANA JSON Web Signature and Encryption Algorithms registry [JWA] and Section 4.1 of the JSON Web Algorithms (JWA) [JWA] specification for lists of encryption algorithms that can be used for CMK encryption. 7. IANA Considerations 7.1. Registration of JWE Header Parameter Names This specification registers the Header Parameter Names defined in Section 4.1 in the IANA JSON Web Signature and Encryption Header Parameters registry [JWS]. Jones, et al. Expires June 30, 2013 [Page 20] Internet-Draft JWE December 2012 7.1.1. Registry Contents o Header Parameter Name: "alg" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.1 of [[ this document ]] o Header Parameter Name: "enc" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.2 of [[ this document ]] o Header Parameter Name: "epk" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.3 of [[ this document ]] o Header Parameter Name: "zip" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.4 of [[ this document ]] o Header Parameter Name: "jku" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.5 of [[ this document ]] o Header Parameter Name: "jwk" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification document(s): Section 4.1.6 of [[ this document ]] o Header Parameter Name: "x5u" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.7 of [[ this document ]] o Header Parameter Name: "x5t" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.8 of [[ this document ]] o Header Parameter Name: "x5c" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.9 of [[ this document ]] Jones, et al. Expires June 30, 2013 [Page 21] Internet-Draft JWE December 2012 o Header Parameter Name: "kid" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.10 of [[ this document ]] o Header Parameter Name: "typ" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.11 of [[ this document ]] o Header Parameter Name: "cty" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.12 of [[ this document ]] o Header Parameter Name: "apu" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.13 of [[ this document ]] o Header Parameter Name: "apv" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.14 of [[ this document ]] o Header Parameter Name: "epu" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.15 of [[ this document ]] o Header Parameter Name: "epv" o Header Parameter Usage Location(s): JWE o Change Controller: IETF o Specification Document(s): Section 4.1.16 of [[ this document ]] 7.2. JSON Web Signature and Encryption Type Values Registration 7.2.1. Registry Contents This specification registers the "JWE" type value in the IANA JSON Web Signature and Encryption Type Values registry [JWS]: o "typ" Header Parameter Value: "JWE" o Abbreviation for MIME Type: application/jwe o Change Controller: IETF o Specification Document(s): Section 4.1.11 of [[ this document ]] Jones, et al. Expires June 30, 2013 [Page 22] Internet-Draft JWE December 2012 7.3. Media Type Registration 7.3.1. Registry Contents This specification registers the "application/jwe" Media Type [RFC2046] in the MIME Media Type registry [RFC4288] to indicate that the content is a JWE using the Compact Serialization. o Type Name: application o Subtype Name: jwe o Required Parameters: n/a o Optional Parameters: n/a o Encoding considerations: JWE values are encoded as a series of base64url encoded values (some of which may be the empty string) separated by period ('.') characters o Security Considerations: See the Security Considerations section of this document o Interoperability Considerations: n/a o Published Specification: [[ this document ]] o Applications that use this media type: OpenID Connect and other applications using encrypted JWTs o Additional Information: Magic number(s): n/a, File extension(s): n/a, Macintosh file type code(s): n/a o Person & email address to contact for further information: Michael B. Jones, mbj@microsoft.com o Intended Usage: COMMON o Restrictions on Usage: none o Author: Michael B. Jones, mbj@microsoft.com o Change Controller: IETF 8. 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 and symmetric keys, 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. All the security considerations in the JWS specification also apply to this specification. Likewise, all the security considerations in XML Encryption 1.1 [W3C.CR-xmlenc-core1-20120313] also apply to JWE, other than those that are XML specific. 9. References Jones, et al. Expires June 30, 2013 [Page 23] Internet-Draft JWE December 2012 9.1. Normative References [ITU.X690.1994] International Telecommunications Union, "Information Technology - ASN.1 encoding rules: Specification of Basic Encoding Rules (BER), Canonical Encoding Rules (CER) and Distinguished Encoding Rules (DER)", ITU-T Recommendation X.690, 1994. [JWA] Jones, M., "JSON Web Algorithms (JWA)", draft-ietf-jose-json-web-algorithms (work in progress), December 2012. [JWK] Jones, M., "JSON Web Key (JWK)", draft-ietf-jose-json-web-key (work in progress), December 2012. [JWS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Signature (JWS)", draft-ietf-jose-json-web-signature (work in progress), December 2012. [RFC1421] Linn, J., "Privacy Enhancement for Internet Electronic Mail: Part I: Message Encryption and Authentication Procedures", RFC 1421, February 1993. [RFC1951] Deutsch, P., "DEFLATE Compressed Data Format Specification version 1.3", RFC 1951, May 1996. [RFC2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail Extensions (MIME) Part Two: Media Types", RFC 2046, November 1996. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC2818] Rescorla, E., "HTTP Over TLS", RFC 2818, May 2000. [RFC3629] Yergeau, F., "UTF-8, a transformation format of ISO 10646", STD 63, RFC 3629, November 2003. [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform Resource Identifier (URI): Generic Syntax", STD 66, RFC 3986, January 2005. [RFC4086] Eastlake, D., Schiller, J., and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC 4086, June 2005. [RFC4288] Freed, N. and J. Klensin, "Media Type Specifications and Jones, et al. Expires June 30, 2013 [Page 24] Internet-Draft JWE December 2012 Registration Procedures", BCP 13, RFC 4288, December 2005. [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. [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security (TLS) Protocol Version 1.2", RFC 5246, August 2008. [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., Housley, R., and W. Polk, "Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile", RFC 5280, May 2008. [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, . 9.2. Informative References [I-D.rescorla-jsms] Rescorla, E. and J. Hildebrand, "JavaScript Message Security Format", draft-rescorla-jsms-00 (work in progress), March 2011. [JSE] Bradley, J. and N. Sakimura (editor), "JSON Simple Encryption", September 2010. [JWE-JS] Jones, M., "JSON Web Encryption JSON Serialization (JWE-JS)", draft-jones-jose-jwe-json-serialization (work in progress), December 2012. [RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally Unique IDentifier (UUID) URN Namespace", RFC 4122, July 2005. [RFC5652] Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, RFC 5652, September 2009. Appendix A. JWE Examples This section provides examples of JWE computations. Jones, et al. Expires June 30, 2013 [Page 25] Internet-Draft JWE December 2012 A.1. Example JWE using RSAES OAEP and AES GCM This example encrypts the plaintext "Live long and prosper." to the recipient using RSAES OAEP and AES GCM. The AES GCM algorithm has an integrated integrity check. The representation of this plaintext is: [76, 105, 118, 101, 32, 108, 111, 110, 103, 32, 97, 110, 100, 32, 112, 114, 111, 115, 112, 101, 114, 46] A.1.1. JWE Header The following example JWE Header declares that: o the Content Master Key is encrypted to the recipient using the RSAES OAEP algorithm to produce the JWE Encrypted Key and o the Plaintext is encrypted using the AES GCM algorithm with a 256 bit key to produce the Ciphertext. {"alg":"RSA-OAEP","enc":"A256GCM"} A.1.2. Encoded JWE Header Base64url encoding the bytes of the UTF-8 representation of the JWE Header yields this Encoded JWE Header value: eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ A.1.3. Content Master Key (CMK) Generate a 256 bit random Content Master Key (CMK). In this example, the value is: [177, 161, 244, 128, 84, 143, 225, 115, 63, 180, 3, 255, 107, 154, 212, 246, 138, 7, 110, 91, 112, 46, 34, 105, 47, 130, 203, 46, 122, 234, 64, 252] A.1.4. Key Encryption Encrypt the CMK with the recipient's public key using the RSAES OAEP algorithm to produce the JWE Encrypted Key. In this example, the RSA key parameters are: Jones, et al. Expires June 30, 2013 [Page 26] Internet-Draft JWE December 2012 +-----------+-------------------------------------------------------+ | Parameter | Value | | Name | | +-----------+-------------------------------------------------------+ | Modulus | [161, 168, 84, 34, 133, 176, 208, 173, 46, 176, 163, | | | 110, 57, 30, 135, 227, 9, 31, 226, 128, 84, 92, 116, | | | 241, 70, 248, 27, 227, 193, 62, 5, 91, 241, 145, 224, | | | 205, 141, 176, 184, 133, 239, 43, 81, 103, 9, 161, | | | 153, 157, 179, 104, 123, 51, 189, 34, 152, 69, 97, | | | 69, 78, 93, 140, 131, 87, 182, 169, 101, 92, 142, 3, | | | 22, 167, 8, 212, 56, 35, 79, 210, 222, 192, 208, 252, | | | 49, 109, 138, 173, 253, 210, 166, 201, 63, 102, 74, | | | 5, 158, 41, 90, 144, 108, 160, 79, 10, 89, 222, 231, | | | 172, 31, 227, 197, 0, 19, 72, 81, 138, 78, 136, 221, | | | 121, 118, 196, 17, 146, 10, 244, 188, 72, 113, 55, | | | 221, 162, 217, 171, 27, 57, 233, 210, 101, 236, 154, | | | 199, 56, 138, 239, 101, 48, 198, 186, 202, 160, 76, | | | 111, 234, 71, 57, 183, 5, 211, 171, 136, 126, 64, 40, | | | 75, 58, 89, 244, 254, 107, 84, 103, 7, 236, 69, 163, | | | 18, 180, 251, 58, 153, 46, 151, 174, 12, 103, 197, | | | 181, 161, 162, 55, 250, 235, 123, 110, 17, 11, 158, | | | 24, 47, 133, 8, 199, 235, 107, 126, 130, 246, 73, | | | 195, 20, 108, 202, 176, 214, 187, 45, 146, 182, 118, | | | 54, 32, 200, 61, 201, 71, 243, 1, 255, 131, 84, 37, | | | 111, 211, 168, 228, 45, 192, 118, 27, 197, 235, 232, | | | 36, 10, 230, 248, 190, 82, 182, 140, 35, 204, 108, | | | 190, 253, 186, 186, 27] | | Exponent | [1, 0, 1] | Jones, et al. Expires June 30, 2013 [Page 27] Internet-Draft JWE December 2012 | Private | [144, 183, 109, 34, 62, 134, 108, 57, 44, 252, 10, | | Exponent | 66, 73, 54, 16, 181, 233, 92, 54, 219, 101, 42, 35, | | | 178, 63, 51, 43, 92, 119, 136, 251, 41, 53, 23, 191, | | | 164, 164, 60, 88, 227, 229, 152, 228, 213, 149, 228, | | | 169, 237, 104, 71, 151, 75, 88, 252, 216, 77, 251, | | | 231, 28, 97, 88, 193, 215, 202, 248, 216, 121, 195, | | | 211, 245, 250, 112, 71, 243, 61, 129, 95, 39, 244, | | | 122, 225, 217, 169, 211, 165, 48, 253, 220, 59, 122, | | | 219, 42, 86, 223, 32, 236, 39, 48, 103, 78, 122, 216, | | | 187, 88, 176, 89, 24, 1, 42, 177, 24, 99, 142, 170, | | | 1, 146, 43, 3, 108, 64, 194, 121, 182, 95, 187, 134, | | | 71, 88, 96, 134, 74, 131, 167, 69, 106, 143, 121, 27, | | | 72, 44, 245, 95, 39, 194, 179, 175, 203, 122, 16, | | | 112, 183, 17, 200, 202, 31, 17, 138, 156, 184, 210, | | | 157, 184, 154, 131, 128, 110, 12, 85, 195, 122, 241, | | | 79, 251, 229, 183, 117, 21, 123, 133, 142, 220, 153, | | | 9, 59, 57, 105, 81, 255, 138, 77, 82, 54, 62, 216, | | | 38, 249, 208, 17, 197, 49, 45, 19, 232, 157, 251, | | | 131, 137, 175, 72, 126, 43, 229, 69, 179, 117, 82, | | | 157, 213, 83, 35, 57, 210, 197, 252, 171, 143, 194, | | | 11, 47, 163, 6, 253, 75, 252, 96, 11, 187, 84, 130, | | | 210, 7, 121, 78, 91, 79, 57, 251, 138, 132, 220, 60, | | | 224, 173, 56, 224, 201] | +-----------+-------------------------------------------------------+ The resulting JWE Encrypted Key value is: [51, 101, 241, 165, 179, 145, 41, 236, 202, 75, 60, 208, 47, 255, 121, 248, 104, 226, 185, 212, 65, 78, 169, 255, 162, 100, 188, 207, 220, 96, 161, 22, 251, 47, 66, 112, 229, 75, 4, 111, 25, 173, 200, 121, 246, 79, 189, 102, 173, 146, 228, 142, 14, 12, 167, 200, 27, 133, 138, 37, 180, 249, 4, 56, 123, 192, 162, 156, 246, 231, 235, 217, 240, 45, 158, 213, 195, 154, 2, 142, 86, 61, 198, 210, 34, 225, 92, 7, 128, 227, 4, 227, 55, 183, 69, 0, 59, 162, 71, 145, 98, 238, 0, 70, 40, 123, 159, 37, 115, 18, 16, 157, 236, 138, 117, 166, 18, 45, 181, 125, 112, 170, 168, 82, 129, 80, 166, 242, 150, 97, 17, 217, 109, 251, 51, 35, 39, 236, 107, 95, 43, 154, 4, 227, 206, 187, 75, 13, 51, 231, 115, 79, 67, 72, 145, 54, 225, 164, 60, 195, 120, 188, 69, 113, 3, 182, 21, 189, 79, 82, 122, 46, 196, 199, 254, 252, 7, 119, 5, 32, 144, 143, 173, 11, 99, 205, 120, 106, 231, 51, 231, 77, 73, 252, 197, 221, 142, 254, 151, 7, 6, 203, 65, 108, 117, 121, 15, 95, 43, 111, 13, 94, 242, 226, 150, 94, 121, 72, 144, 251, 69, 93, 137, 178, 13, 216, 8, 227, 125, 110, 180, 157, 250, 207, 184, 232, 222, 164, 193, 70, 232, 16, 65, 109, 29, 251, 164, 119, 50, 205, 236, 109, 245, 234, 78, 1] Jones, et al. Expires June 30, 2013 [Page 28] Internet-Draft JWE December 2012 A.1.5. Encoded JWE Encrypted Key Base64url encode the JWE Encrypted Key to produce the Encoded JWE Encrypted Key. This result (with line breaks for display purposes only) is: M2XxpbORKezKSzzQL_95-GjiudRBTqn_omS8z9xgoRb7L0Jw5UsEbxmtyHn2T71m rZLkjg4Mp8gbhYoltPkEOHvAopz25-vZ8C2e1cOaAo5WPcbSIuFcB4DjBOM3t0UA O6JHkWLuAEYoe58lcxIQneyKdaYSLbV9cKqoUoFQpvKWYRHZbfszIyfsa18rmgTj zrtLDTPnc09DSJE24aQ8w3i8RXEDthW9T1J6LsTH_vwHdwUgkI-tC2PNeGrnM-dN SfzF3Y7-lwcGy0FsdXkPXytvDV7y4pZeeUiQ-0VdibIN2AjjfW60nfrPuOjepMFG 6BBBbR37pHcyzext9epOAQ A.1.6. Initialization Vector Generate a random 96 bit JWE Initialization Vector. In this example, the value is: [227, 197, 117, 252, 2, 219, 233, 68, 180, 225, 77, 219] Base64url encoding this value yields the Encoded JWE Initialization Vector value: 48V1_ALb6US04U3b A.1.7. "Additional Authenticated Data" Parameter Concatenate the Encoded JWE Header value, a period character ('.'), the Encoded JWE Encrypted Key, a second period character ('.'), and the Encoded JWE Initialization Vector to create the "additional authenticated data" parameter for the AES GCM algorithm. This result (with line breaks for display purposes only) is: eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ. M2XxpbORKezKSzzQL_95-GjiudRBTqn_omS8z9xgoRb7L0Jw5UsEbxmtyHn2T71m rZLkjg4Mp8gbhYoltPkEOHvAopz25-vZ8C2e1cOaAo5WPcbSIuFcB4DjBOM3t0UA O6JHkWLuAEYoe58lcxIQneyKdaYSLbV9cKqoUoFQpvKWYRHZbfszIyfsa18rmgTj zrtLDTPnc09DSJE24aQ8w3i8RXEDthW9T1J6LsTH_vwHdwUgkI-tC2PNeGrnM-dN SfzF3Y7-lwcGy0FsdXkPXytvDV7y4pZeeUiQ-0VdibIN2AjjfW60nfrPuOjepMFG 6BBBbR37pHcyzext9epOAQ. 48V1_ALb6US04U3b The representation of this value is: [101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 83, 85, 48, 69, 116, 84, 48, 70, 70, 85, 67, 73, 115, 73, 109, 86, 117, 89, 121, 73, 54, 73, 107, 69, 121, 78, 84, 90, 72, 81, 48, 48, 105, 102, 81, 46, 77, 50, 88, 120, 112, 98, 79, 82, 75, 101, 122, 75, 83, 122, 122, 81, Jones, et al. Expires June 30, 2013 [Page 29] Internet-Draft JWE December 2012 76, 95, 57, 53, 45, 71, 106, 105, 117, 100, 82, 66, 84, 113, 110, 95, 111, 109, 83, 56, 122, 57, 120, 103, 111, 82, 98, 55, 76, 48, 74, 119, 53, 85, 115, 69, 98, 120, 109, 116, 121, 72, 110, 50, 84, 55, 49, 109, 114, 90, 76, 107, 106, 103, 52, 77, 112, 56, 103, 98, 104, 89, 111, 108, 116, 80, 107, 69, 79, 72, 118, 65, 111, 112, 122, 50, 53, 45, 118, 90, 56, 67, 50, 101, 49, 99, 79, 97, 65, 111, 53, 87, 80, 99, 98, 83, 73, 117, 70, 99, 66, 52, 68, 106, 66, 79, 77, 51, 116, 48, 85, 65, 79, 54, 74, 72, 107, 87, 76, 117, 65, 69, 89, 111, 101, 53, 56, 108, 99, 120, 73, 81, 110, 101, 121, 75, 100, 97, 89, 83, 76, 98, 86, 57, 99, 75, 113, 111, 85, 111, 70, 81, 112, 118, 75, 87, 89, 82, 72, 90, 98, 102, 115, 122, 73, 121, 102, 115, 97, 49, 56, 114, 109, 103, 84, 106, 122, 114, 116, 76, 68, 84, 80, 110, 99, 48, 57, 68, 83, 74, 69, 50, 52, 97, 81, 56, 119, 51, 105, 56, 82, 88, 69, 68, 116, 104, 87, 57, 84, 49, 74, 54, 76, 115, 84, 72, 95, 118, 119, 72, 100, 119, 85, 103, 107, 73, 45, 116, 67, 50, 80, 78, 101, 71, 114, 110, 77, 45, 100, 78, 83, 102, 122, 70, 51, 89, 55, 45, 108, 119, 99, 71, 121, 48, 70, 115, 100, 88, 107, 80, 88, 121, 116, 118, 68, 86, 55, 121, 52, 112, 90, 101, 101, 85, 105, 81, 45, 48, 86, 100, 105, 98, 73, 78, 50, 65, 106, 106, 102, 87, 54, 48, 110, 102, 114, 80, 117, 79, 106, 101, 112, 77, 70, 71, 54, 66, 66, 66, 98, 82, 51, 55, 112, 72, 99, 121, 122, 101, 120, 116, 57, 101, 112, 79, 65, 81, 46, 52, 56, 86, 49, 95, 65, 76, 98, 54, 85, 83, 48, 52, 85, 51, 98] A.1.8. Plaintext Encryption Encrypt the Plaintext with AES GCM using the CMK as the encryption key, the JWE Initialization Vector, and the "additional authenticated data" value above, requesting a 128 bit "authentication tag" output. The resulting Ciphertext is: [253, 237, 181, 180, 97, 161, 105, 207, 233, 120, 65, 100, 45, 122, 246, 116, 195, 212, 102, 37, 36, 175] The resulting "authentication tag" value is: [237, 94, 89, 14, 74, 52, 191, 249, 159, 216, 240, 28, 224, 147, 34, 82] A.1.9. Encoded JWE Ciphertext Base64url encode the resulting Ciphertext to create the Encoded JWE Ciphertext. This result is: _e21tGGhac_peEFkLXr2dMPUZiUkrw Jones, et al. Expires June 30, 2013 [Page 30] Internet-Draft JWE December 2012 A.1.10. Encoded JWE Integrity Value Base64url encode the resulting "authentication tag" to create the Encoded JWE Integrity Value. This result is: 7V5ZDko0v_mf2PAc4JMiUg A.1.11. Complete Representation Assemble the final representation: The Compact Serialization of this result is the concatenation of the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value in that order, with the five strings being separated by four period ('.') characters. The final result in this example (with line breaks for display purposes only) is: eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ. M2XxpbORKezKSzzQL_95-GjiudRBTqn_omS8z9xgoRb7L0Jw5UsEbxmtyHn2T71m rZLkjg4Mp8gbhYoltPkEOHvAopz25-vZ8C2e1cOaAo5WPcbSIuFcB4DjBOM3t0UA O6JHkWLuAEYoe58lcxIQneyKdaYSLbV9cKqoUoFQpvKWYRHZbfszIyfsa18rmgTj zrtLDTPnc09DSJE24aQ8w3i8RXEDthW9T1J6LsTH_vwHdwUgkI-tC2PNeGrnM-dN SfzF3Y7-lwcGy0FsdXkPXytvDV7y4pZeeUiQ-0VdibIN2AjjfW60nfrPuOjepMFG 6BBBbR37pHcyzext9epOAQ. 48V1_ALb6US04U3b. _e21tGGhac_peEFkLXr2dMPUZiUkrw. 7V5ZDko0v_mf2PAc4JMiUg A.1.12. Validation This example illustrates the process of creating a JWE with an Authenticated Encryption algorithm. These results can be used to validate JWE decryption implementations for these algorithms. Note that since the RSAES OAEP computation includes random values, the encryption results above will not be completely reproducible. However, since the AES GCM computation is deterministic, the JWE Encrypted Ciphertext values will be the same for all encryptions performed using these inputs. A.2. Example JWE using RSAES-PKCS1-V1_5 and AES CBC This example encrypts the plaintext "No matter where you go, there you are." to the recipient using RSAES-PKCS1-V1_5 and AES CBC. AES CBC does not have an integrated integrity check, so a separate integrity check calculation is performed using HMAC SHA-256, with separate encryption and integrity keys being derived from a master Jones, et al. Expires June 30, 2013 [Page 31] Internet-Draft JWE December 2012 key using the Concat KDF with the SHA-256 digest function. The representation of this plaintext is: [78, 111, 32, 109, 97, 116, 116, 101, 114, 32, 119, 104, 101, 114, 101, 32, 121, 111, 117, 32, 103, 111, 44, 32, 116, 104, 101, 114, 101, 32, 121, 111, 117, 32, 97, 114, 101, 46] A.2.1. JWE Header The following example JWE Header (with line breaks for display purposes only) declares that: o the Content Master Key is encrypted to the recipient using the RSAES-PKCS1-V1_5 algorithm to produce the JWE Encrypted Key and o the Plaintext is encrypted using the AES CBC algorithm with a 128 bit key to produce the Ciphertext, with the integrity of the Ciphertext and the parameters used to create it being secured with the HMAC SHA-256 algorithm. {"alg":"RSA1_5","enc":"A128CBC+HS256"} A.2.2. Encoded JWE Header Base64url encoding the bytes of the UTF-8 representation of the JWE Header yields this Encoded JWE Header value: eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDK0hTMjU2In0 A.2.3. Content Master Key (CMK) Generate a 256 bit random Content Master Key (CMK). In this example, the key value is: [4, 211, 31, 197, 84, 157, 252, 254, 11, 100, 157, 250, 63, 170, 106, 206, 107, 124, 212, 45, 111, 107, 9, 219, 200, 177, 0, 240, 143, 156, 44, 207] A.2.4. Key Encryption Encrypt the CMK with the recipient's public key using the RSAES- PKCS1-V1_5 algorithm to produce the JWE Encrypted Key. In this example, the RSA key parameters are: Jones, et al. Expires June 30, 2013 [Page 32] Internet-Draft JWE December 2012 +-----------+-------------------------------------------------------+ | Parameter | Value | | Name | | +-----------+-------------------------------------------------------+ | Modulus | [177, 119, 33, 13, 164, 30, 108, 121, 207, 136, 107, | | | 242, 12, 224, 19, 226, 198, 134, 17, 71, 173, 75, 42, | | | 61, 48, 162, 206, 161, 97, 108, 185, 234, 226, 219, | | | 118, 206, 118, 5, 169, 224, 60, 181, 90, 85, 51, 123, | | | 6, 224, 4, 122, 29, 230, 151, 12, 244, 127, 121, 25, | | | 4, 85, 220, 144, 215, 110, 130, 17, 68, 228, 129, | | | 138, 7, 130, 231, 40, 212, 214, 17, 179, 28, 124, | | | 151, 178, 207, 20, 14, 154, 222, 113, 176, 24, 198, | | | 73, 211, 113, 9, 33, 178, 80, 13, 25, 21, 25, 153, | | | 212, 206, 67, 154, 147, 70, 194, 192, 183, 160, 83, | | | 98, 236, 175, 85, 23, 97, 75, 199, 177, 73, 145, 50, | | | 253, 206, 32, 179, 254, 236, 190, 82, 73, 67, 129, | | | 253, 252, 220, 108, 136, 138, 11, 192, 1, 36, 239, | | | 228, 55, 81, 113, 17, 25, 140, 63, 239, 146, 3, 172, | | | 96, 60, 227, 233, 64, 255, 224, 173, 225, 228, 229, | | | 92, 112, 72, 99, 97, 26, 87, 187, 123, 46, 50, 90, | | | 202, 117, 73, 10, 153, 47, 224, 178, 163, 77, 48, 46, | | | 154, 33, 148, 34, 228, 33, 172, 216, 89, 46, 225, | | | 127, 68, 146, 234, 30, 147, 54, 146, 5, 133, 45, 78, | | | 254, 85, 55, 75, 213, 86, 194, 218, 215, 163, 189, | | | 194, 54, 6, 83, 36, 18, 153, 53, 7, 48, 89, 35, 66, | | | 144, 7, 65, 154, 13, 97, 75, 55, 230, 132, 3, 13, | | | 239, 71] | | Exponent | [1, 0, 1] | Jones, et al. Expires June 30, 2013 [Page 33] Internet-Draft JWE December 2012 | Private | [84, 80, 150, 58, 165, 235, 242, 123, 217, 55, 38, | | Exponent | 154, 36, 181, 221, 156, 211, 215, 100, 164, 90, 88, | | | 40, 228, 83, 148, 54, 122, 4, 16, 165, 48, 76, 194, | | | 26, 107, 51, 53, 179, 165, 31, 18, 198, 173, 78, 61, | | | 56, 97, 252, 158, 140, 80, 63, 25, 223, 156, 36, 203, | | | 214, 252, 120, 67, 180, 167, 3, 82, 243, 25, 97, 214, | | | 83, 133, 69, 16, 104, 54, 160, 200, 41, 83, 164, 187, | | | 70, 153, 111, 234, 242, 158, 175, 28, 198, 48, 211, | | | 45, 148, 58, 23, 62, 227, 74, 52, 117, 42, 90, 41, | | | 249, 130, 154, 80, 119, 61, 26, 193, 40, 125, 10, | | | 152, 174, 227, 225, 205, 32, 62, 66, 6, 163, 100, 99, | | | 219, 19, 253, 25, 105, 80, 201, 29, 252, 157, 237, | | | 69, 1, 80, 171, 167, 20, 196, 156, 109, 249, 88, 0, | | | 3, 152, 38, 165, 72, 87, 6, 152, 71, 156, 214, 16, | | | 71, 30, 82, 51, 103, 76, 218, 63, 9, 84, 163, 249, | | | 91, 215, 44, 238, 85, 101, 240, 148, 1, 82, 224, 91, | | | 135, 105, 127, 84, 171, 181, 152, 210, 183, 126, 24, | | | 46, 196, 90, 173, 38, 245, 219, 186, 222, 27, 240, | | | 212, 194, 15, 66, 135, 226, 178, 190, 52, 245, 74, | | | 65, 224, 81, 100, 85, 25, 204, 165, 203, 187, 175, | | | 84, 100, 82, 15, 11, 23, 202, 151, 107, 54, 41, 207, | | | 3, 136, 229, 134, 131, 93, 139, 50, 182, 204, 93, | | | 130, 89] | +-----------+-------------------------------------------------------+ The resulting JWE Encrypted Key value is: [102, 105, 229, 169, 104, 35, 95, 42, 176, 142, 190, 220, 92, 124, 172, 240, 94, 253, 106, 114, 20, 35, 162, 118, 81, 103, 64, 201, 20, 4, 112, 96, 84, 248, 163, 199, 177, 227, 204, 247, 93, 63, 70, 132, 195, 26, 237, 72, 91, 141, 3, 159, 71, 111, 113, 213, 68, 142, 146, 92, 60, 243, 72, 111, 53, 156, 51, 16, 226, 215, 125, 68, 141, 232, 62, 111, 197, 98, 91, 150, 23, 230, 132, 93, 97, 216, 145, 226, 3, 18, 12, 48, 119, 153, 185, 8, 156, 195, 84, 21, 63, 143, 43, 144, 174, 101, 25, 199, 7, 106, 212, 43, 151, 225, 62, 225, 122, 92, 90, 139, 45, 144, 134, 229, 15, 235, 38, 110, 132, 189, 236, 126, 92, 183, 13, 64, 2, 77, 107, 95, 186, 8, 133, 53, 217, 104, 247, 152, 241, 49, 199, 15, 111, 110, 123, 16, 13, 78, 193, 224, 23, 230, 133, 220, 162, 126, 82, 192, 236, 7, 185, 100, 106, 21, 70, 93, 192, 255, 252, 139, 61, 124, 81, 140, 113, 97, 164, 231, 131, 167, 246, 157, 199, 195, 114, 122, 49, 121, 115, 63, 114, 12, 165, 11, 186, 3, 108, 12, 199, 101, 29, 226, 80, 56, 193, 149, 45, 134, 146, 102, 221, 202, 63, 166, 150, 53, 42, 133, 3, 83, 199, 14, 15, 181, 209, 199, 174, 76, 75, 106, 254, 243, 196, 227, 225, 173, 122, 254, 13, 224, 174, 4, 185, 217, 99, 225] Jones, et al. Expires June 30, 2013 [Page 34] Internet-Draft JWE December 2012 A.2.5. Encoded JWE Encrypted Key Base64url encode the JWE Encrypted Key to produce the Encoded JWE Encrypted Key. This result (with line breaks for display purposes only) is: ZmnlqWgjXyqwjr7cXHys8F79anIUI6J2UWdAyRQEcGBU-KPHsePM910_RoTDGu1I W40Dn0dvcdVEjpJcPPNIbzWcMxDi131Ejeg-b8ViW5YX5oRdYdiR4gMSDDB3mbkI nMNUFT-PK5CuZRnHB2rUK5fhPuF6XFqLLZCG5Q_rJm6Evex-XLcNQAJNa1-6CIU1 2Wj3mPExxw9vbnsQDU7B4BfmhdyiflLA7Ae5ZGoVRl3A__yLPXxRjHFhpOeDp_ad x8NyejF5cz9yDKULugNsDMdlHeJQOMGVLYaSZt3KP6aWNSqFA1PHDg-10ceuTEtq _vPE4-Gtev4N4K4Eudlj4Q A.2.6. Key Derivation Use the Concat key derivation function to derive Content Encryption Key (CEK) and Content Integrity Key (CIK) values from the CMK. The details of this derivation are shown in Appendix A.4. The resulting CEK value is: [203, 165, 180, 113, 62, 195, 22, 98, 91, 153, 210, 38, 112, 35, 230, 236] The resulting CIK value is: [218, 24, 160, 17, 160, 50, 235, 35, 216, 209, 100, 174, 155, 163, 10, 117, 180, 111, 172, 200, 127, 201, 206, 173, 40, 45, 58, 170, 35, 93, 9, 60] A.2.7. Initialization Vector Generate a random 128 bit JWE Initialization Vector. In this example, the value is: [3, 22, 60, 12, 43, 67, 104, 105, 108, 108, 105, 99, 111, 116, 104, 101] Base64url encoding this value yields the Encoded JWE Initialization Vector value: AxY8DCtDaGlsbGljb3RoZQ A.2.8. Plaintext Encryption Encrypt the Plaintext with AES CBC using the CEK and the JWE Initialization Vector to produce the Ciphertext. The resulting Ciphertext is: Jones, et al. Expires June 30, 2013 [Page 35] Internet-Draft JWE December 2012 [71, 27, 35, 131, 163, 200, 19, 23, 38, 25, 33, 123, 46, 116, 132, 144, 58, 150, 32, 167, 192, 195, 92, 25, 207, 101, 233, 105, 181, 121, 63, 4, 44, 162, 82, 176, 17, 171, 150, 97, 147, 68, 245, 13, 97, 100, 145, 25] A.2.9. Encoded JWE Ciphertext Base64url encode the resulting Ciphertext to create the Encoded JWE Ciphertext. This result is: Rxsjg6PIExcmGSF7LnSEkDqWIKfAw1wZz2XpabV5PwQsolKwEauWYZNE9Q1hZJEZ A.2.10. Secured Input Value Concatenate the Encoded JWE Header value, a period character ('.'), the Encoded JWE Encrypted Key, a second period character, the Encoded JWE Initialization Vector, a third period ('.') character, and the Encoded JWE Ciphertext to create the value to integrity protect. This result (with line breaks for display purposes only) is: eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDK0hTMjU2In0. ZmnlqWgjXyqwjr7cXHys8F79anIUI6J2UWdAyRQEcGBU-KPHsePM910_RoTDGu1I W40Dn0dvcdVEjpJcPPNIbzWcMxDi131Ejeg-b8ViW5YX5oRdYdiR4gMSDDB3mbkI nMNUFT-PK5CuZRnHB2rUK5fhPuF6XFqLLZCG5Q_rJm6Evex-XLcNQAJNa1-6CIU1 2Wj3mPExxw9vbnsQDU7B4BfmhdyiflLA7Ae5ZGoVRl3A__yLPXxRjHFhpOeDp_ad x8NyejF5cz9yDKULugNsDMdlHeJQOMGVLYaSZt3KP6aWNSqFA1PHDg-10ceuTEtq _vPE4-Gtev4N4K4Eudlj4Q. AxY8DCtDaGlsbGljb3RoZQ. Rxsjg6PIExcmGSF7LnSEkDqWIKfAw1wZz2XpabV5PwQsolKwEauWYZNE9Q1hZJEZ The representation of this value is: [101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 83, 85, 48, 69, 120, 88, 122, 85, 105, 76, 67, 74, 108, 98, 109, 77, 105, 79, 105, 74, 66, 77, 84, 73, 52, 81, 48, 74, 68, 75, 48, 104, 84, 77, 106, 85, 50, 73, 110, 48, 46, 90, 109, 110, 108, 113, 87, 103, 106, 88, 121, 113, 119, 106, 114, 55, 99, 88, 72, 121, 115, 56, 70, 55, 57, 97, 110, 73, 85, 73, 54, 74, 50, 85, 87, 100, 65, 121, 82, 81, 69, 99, 71, 66, 85, 45, 75, 80, 72, 115, 101, 80, 77, 57, 49, 48, 95, 82, 111, 84, 68, 71, 117, 49, 73, 87, 52, 48, 68, 110, 48, 100, 118, 99, 100, 86, 69, 106, 112, 74, 99, 80, 80, 78, 73, 98, 122, 87, 99, 77, 120, 68, 105, 49, 51, 49, 69, 106, 101, 103, 45, 98, 56, 86, 105, 87, 53, 89, 88, 53, 111, 82, 100, 89, 100, 105, 82, 52, 103, 77, 83, 68, 68, 66, 51, 109, 98, 107, 73, 110, 77, 78, 85, 70, 84, 45, 80, 75, 53, 67, 117, 90, 82, 110, 72, 66, 50, 114, 85, 75, 53, 102, 104, 80, 117, 70, 54, 88, 70, 113, 76, 76, 90, 67, 71, 53, 81, 95, 114, 74, 109, 54, 69, 118, 101, 120, 45, 88, 76, 99, 78, 81, 65, 74, 78, 97, 49, 45, 54, 67, 73, 85, 49, 50, 87, 106, 51, 109, 80, 69, 120, 120, Jones, et al. Expires June 30, 2013 [Page 36] Internet-Draft JWE December 2012 119, 57, 118, 98, 110, 115, 81, 68, 85, 55, 66, 52, 66, 102, 109, 104, 100, 121, 105, 102, 108, 76, 65, 55, 65, 101, 53, 90, 71, 111, 86, 82, 108, 51, 65, 95, 95, 121, 76, 80, 88, 120, 82, 106, 72, 70, 104, 112, 79, 101, 68, 112, 95, 97, 100, 120, 56, 78, 121, 101, 106, 70, 53, 99, 122, 57, 121, 68, 75, 85, 76, 117, 103, 78, 115, 68, 77, 100, 108, 72, 101, 74, 81, 79, 77, 71, 86, 76, 89, 97, 83, 90, 116, 51, 75, 80, 54, 97, 87, 78, 83, 113, 70, 65, 49, 80, 72, 68, 103, 45, 49, 48, 99, 101, 117, 84, 69, 116, 113, 95, 118, 80, 69, 52, 45, 71, 116, 101, 118, 52, 78, 52, 75, 52, 69, 117, 100, 108, 106, 52, 81, 46, 65, 120, 89, 56, 68, 67, 116, 68, 97, 71, 108, 115, 98, 71, 108, 106, 98, 51, 82, 111, 90, 81, 46, 82, 120, 115, 106, 103, 54, 80, 73, 69, 120, 99, 109, 71, 83, 70, 55, 76, 110, 83, 69, 107, 68, 113, 87, 73, 75, 102, 65, 119, 49, 119, 90, 122, 50, 88, 112, 97, 98, 86, 53, 80, 119, 81, 115, 111, 108, 75, 119, 69, 97, 117, 87, 89, 90, 78, 69, 57, 81, 49, 104, 90, 74, 69, 90] A.2.11. JWE Integrity Value Compute the HMAC SHA-256 of this value using the CIK to create the JWE Integrity Value. This result is: [240, 181, 234, 49, 221, 9, 44, 107, 49, 49, 160, 121, 186, 131, 90, 50, 152, 59, 185, 69, 191, 167, 141, 17, 149, 166, 71, 11, 3, 8, 203, 57] A.2.12. Encoded JWE Integrity Value Base64url encode the resulting JWE Integrity Value to create the Encoded JWE Integrity Value. This result is: 8LXqMd0JLGsxMaB5uoNaMpg7uUW_p40RlaZHCwMIyzk A.2.13. Complete Representation Assemble the final representation: The Compact Serialization of this result is the concatenation of the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value in that order, with the five strings being separated by four period ('.') characters. The final result in this example (with line breaks for display purposes only) is: Jones, et al. Expires June 30, 2013 [Page 37] Internet-Draft JWE December 2012 eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDK0hTMjU2In0. ZmnlqWgjXyqwjr7cXHys8F79anIUI6J2UWdAyRQEcGBU-KPHsePM910_RoTDGu1I W40Dn0dvcdVEjpJcPPNIbzWcMxDi131Ejeg-b8ViW5YX5oRdYdiR4gMSDDB3mbkI nMNUFT-PK5CuZRnHB2rUK5fhPuF6XFqLLZCG5Q_rJm6Evex-XLcNQAJNa1-6CIU1 2Wj3mPExxw9vbnsQDU7B4BfmhdyiflLA7Ae5ZGoVRl3A__yLPXxRjHFhpOeDp_ad x8NyejF5cz9yDKULugNsDMdlHeJQOMGVLYaSZt3KP6aWNSqFA1PHDg-10ceuTEtq _vPE4-Gtev4N4K4Eudlj4Q. AxY8DCtDaGlsbGljb3RoZQ. Rxsjg6PIExcmGSF7LnSEkDqWIKfAw1wZz2XpabV5PwQsolKwEauWYZNE9Q1hZJEZ. 8LXqMd0JLGsxMaB5uoNaMpg7uUW_p40RlaZHCwMIyzk A.2.14. Validation This example illustrates the process of creating a JWE with a composite Authenticated Encryption algorithm created from a non- Authenticated Encryption algorithm by adding a separate integrity check calculation. These results can be used to validate JWE decryption implementations for these algorithms. Note that since the RSAES-PKCS1-V1_5 computation includes random values, the encryption results above will not be completely reproducible. However, since the AES CBC computation is deterministic, the JWE Encrypted Ciphertext values will be the same for all encryptions performed using these inputs. A.3. Example JWE using AES Key Wrap and AES GCM This example encrypts the plaintext "The true sign of intelligence is not knowledge but imagination." to the recipient using AES Key Wrap and AES GCM. The representation of this plaintext is: [84, 104, 101, 32, 116, 114, 117, 101, 32, 115, 105, 103, 110, 32, 111, 102, 32, 105, 110, 116, 101, 108, 108, 105, 103, 101, 110, 99, 101, 32, 105, 115, 32, 110, 111, 116, 32, 107, 110, 111, 119, 108, 101, 100, 103, 101, 32, 98, 117, 116, 32, 105, 109, 97, 103, 105, 110, 97, 116, 105, 111, 110, 46] A.3.1. JWE Header The following example JWE Header declares that: o the Content Master Key is encrypted to the recipient using the AES Key Wrap algorithm with a 128 bit key to produce the JWE Encrypted Key and o the Plaintext is encrypted using the AES GCM algorithm with a 128 bit key to produce the Ciphertext. Jones, et al. Expires June 30, 2013 [Page 38] Internet-Draft JWE December 2012 {"alg":"A128KW","enc":"A128GCM"} A.3.2. Encoded JWE Header Base64url encoding the bytes of the UTF-8 representation of the JWE Header yields this Encoded JWE Header value: eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIn0 A.3.3. Content Master Key (CMK) Generate a 128 bit random Content Master Key (CMK). In this example, the value is: [64, 154, 239, 170, 64, 40, 195, 99, 19, 84, 192, 142, 192, 238, 207, 217] A.3.4. Key Encryption Encrypt the CMK with the shared symmetric key using the AES Key Wrap algorithm to produce the JWE Encrypted Key. In this example, the shared symmetric key value is: [25, 172, 32, 130, 225, 114, 26, 181, 138, 106, 254, 192, 95, 133, 74, 82] The resulting JWE Encrypted Key value is: [164, 255, 251, 1, 64, 200, 65, 200, 34, 197, 81, 143, 43, 211, 240, 38, 191, 161, 181, 117, 119, 68, 44, 80] A.3.5. Encoded JWE Encrypted Key Base64url encode the JWE Encrypted Key to produce the Encoded JWE Encrypted Key. This result is: pP_7AUDIQcgixVGPK9PwJr-htXV3RCxQ A.3.6. Initialization Vector Generate a random 96 bit JWE Initialization Vector. In this example, the value is: [253, 220, 80, 25, 166, 152, 178, 168, 97, 99, 67, 89] Base64url encoding this value yields the Encoded JWE Initialization Vector value: Jones, et al. Expires June 30, 2013 [Page 39] Internet-Draft JWE December 2012 _dxQGaaYsqhhY0NZ A.3.7. "Additional Authenticated Data" Parameter Concatenate the Encoded JWE Header value, a period character ('.'), the Encoded JWE Encrypted Key, a second period character ('.'), and the Encoded JWE Initialization Vector to create the "additional authenticated data" parameter for the AES GCM algorithm. This result (with line breaks for display purposes only) is: eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIn0. pP_7AUDIQcgixVGPK9PwJr-htXV3RCxQ. _dxQGaaYsqhhY0NZ The representation of this value is: [101, 121, 74, 104, 98, 71, 99, 105, 79, 105, 74, 66, 77, 84, 73, 52, 83, 49, 99, 105, 76, 67, 74, 108, 98, 109, 77, 105, 79, 105, 74, 66, 77, 84, 73, 52, 82, 48, 78, 78, 73, 110, 48, 46, 112, 80, 95, 55, 65, 85, 68, 73, 81, 99, 103, 105, 120, 86, 71, 80, 75, 57, 80, 119, 74, 114, 45, 104, 116, 88, 86, 51, 82, 67, 120, 81, 46, 95, 100, 120, 81, 71, 97, 97, 89, 115, 113, 104, 104, 89, 48, 78, 90] A.3.8. Plaintext Encryption Encrypt the Plaintext with AES GCM using the CMK as the encryption key, the JWE Initialization Vector, and the "additional authenticated data" value above, requesting a 128 bit "authentication tag" output. The resulting Ciphertext is: [227, 12, 89, 132, 185, 16, 248, 93, 145, 87, 53, 130, 95, 115, 62, 104, 138, 96, 109, 71, 124, 211, 165, 103, 202, 99, 21, 193, 4, 226, 84, 229, 254, 106, 144, 241, 39, 86, 148, 132, 160, 104, 88, 232, 228, 109, 85, 7, 86, 80, 134, 106, 166, 24, 92, 199, 210, 188, 153, 187, 218, 69, 227] The resulting "authentication tag" value is: [154, 35, 80, 107, 37, 148, 81, 6, 103, 4, 60, 206, 171, 165, 113, 67] A.3.9. Encoded JWE Ciphertext Base64url encode the resulting Ciphertext to create the Encoded JWE Ciphertext. This result (with line breaks for display purposes only) is: 4wxZhLkQ-F2RVzWCX3M-aIpgbUd806VnymMVwQTiVOX-apDxJ1aUhKBoWOjkbVUH Jones, et al. Expires June 30, 2013 [Page 40] Internet-Draft JWE December 2012 VlCGaqYYXMfSvJm72kXj A.3.10. Encoded JWE Integrity Value Base64url encode the resulting "authentication tag" to create the Encoded JWE Integrity Value. This result is: miNQayWUUQZnBDzOq6VxQw A.3.11. Complete Representation Assemble the final representation: The Compact Serialization of this result is the concatenation of the Encoded JWE Header, the Encoded JWE Encrypted Key, the Encoded JWE Initialization Vector, the Encoded JWE Ciphertext, and the Encoded JWE Integrity Value in that order, with the five strings being separated by four period ('.') characters. The final result in this example (with line breaks for display purposes only) is: eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4R0NNIn0. pP_7AUDIQcgixVGPK9PwJr-htXV3RCxQ. _dxQGaaYsqhhY0NZ. 4wxZhLkQ-F2RVzWCX3M-aIpgbUd806VnymMVwQTiVOX-apDxJ1aUhKBoWOjkbVUH VlCGaqYYXMfSvJm72kXj. miNQayWUUQZnBDzOq6VxQw A.3.12. Validation This example illustrates the process of creating a JWE with symmetric key wrap and an Authenticated Encryption algorithm. These results can be used to validate JWE decryption implementations for these algorithms. Also, since both the AES Key Wrap and AES GCM computations are deterministic, the resulting JWE value will be the same for all encryptions performed using these inputs. Since the computation is reproducible, these results can also be used to validate JWE encryption implementations for these algorithms. A.4. Example Key Derivation for "enc" value "A128CBC+HS256" This example uses the Concat KDF to derive the Content Encryption Key (CEK) and Content Integrity Key (CIK) from the Content Master Key (CMK) in the manner described in Section 4.8.1 of [JWA]. In this example, a 256 bit CMK is used to derive a 128 bit CEK and a 256 bit CIK. The CMK value used is: Jones, et al. Expires June 30, 2013 [Page 41] Internet-Draft JWE December 2012 [4, 211, 31, 197, 84, 157, 252, 254, 11, 100, 157, 250, 63, 170, 106, 206, 107, 124, 212, 45, 111, 107, 9, 219, 200, 177, 0, 240, 143, 156, 44, 207] A.4.1. CEK Generation These values are concatenated to produce the round 1 hash input: o the round number 1 as a 32 bit big endian integer ([0, 0, 0, 1]), o the CMK value (as above), o the output bit size 128 as a 32 bit big endian number ([0, 0, 0, 128]), o the bytes of the UTF-8 representation of the "enc" value "A128CBC+HS256" -- [65, 49, 50, 56, 67, 66, 67, 43, 72, 83, 50, 53, 54], o the Datalen value of zero for the omitted "epu" (encryption PartyUInfo) value ([0, 0, 0, 0]), o the Datalen value of zero for the omitted "epv" (encryption PartyVInfo) value ([0, 0, 0, 0]), o the bytes of the ASCII representation of the label "Encryption" -- [69, 110, 99, 114, 121, 112, 116, 105, 111, 110]. Thus the round 1 hash input is: [0, 0, 0, 1, 4, 211, 31, 197, 84, 157, 252, 254, 11, 100, 157, 250, 63, 170, 106, 206, 107, 124, 212, 45, 111, 107, 9, 219, 200, 177, 0, 240, 143, 156, 44, 207, 0, 0, 0, 128, 65, 49, 50, 56, 67, 66, 67, 43, 72, 83, 50, 53, 54, 0, 0, 0, 0, 0, 0, 0, 0, 69, 110, 99, 114, 121, 112, 116, 105, 111, 110] The SHA-256 hash of this value, which is the round 1 hash output, is: [203, 165, 180, 113, 62, 195, 22, 98, 91, 153, 210, 38, 112, 35, 230, 236, 181, 193, 129, 233, 251, 107, 70, 80, 36, 150, 216, 251, 182, 29, 104, 150] Given that 128 bits are needed for the CEK and the hash has produced 256 bits, the CEK value is the first 128 bits of that value: [203, 165, 180, 113, 62, 195, 22, 98, 91, 153, 210, 38, 112, 35, 230, 236] Jones, et al. Expires June 30, 2013 [Page 42] Internet-Draft JWE December 2012 A.4.2. CIK Generation These values are concatenated to produce the round 1 hash input: o the round number 1 as a 32 bit big endian integer ([0, 0, 0, 1]), o the CMK value (as above), o the output bit size 256 as a 32 bit big endian number ([0, 0, 1, 0]), o the bytes of the UTF-8 representation of the "enc" value "A128CBC+HS256" -- [65, 49, 50, 56, 67, 66, 67, 43, 72, 83, 50, 53, 54], o the Datalen value of zero for the omitted "epu" (encryption PartyUInfo) value ([0, 0, 0, 0]), o the Datalen value of zero for the omitted "epv" (encryption PartyVInfo) value ([0, 0, 0, 0]), o the bytes of the ASCII representation of the label "Integrity" -- [73, 110, 116, 101, 103, 114, 105, 116, 121]. Thus the round 1 hash input is: [0, 0, 0, 1, 4, 211, 31, 197, 84, 157, 252, 254, 11, 100, 157, 250, 63, 170, 106, 206, 107, 124, 212, 45, 111, 107, 9, 219, 200, 177, 0, 240, 143, 156, 44, 207, 0, 0, 1, 0, 65, 49, 50, 56, 67, 66, 67, 43, 72, 83, 50, 53, 54, 0, 0, 0, 0, 0, 0, 0, 0, 73, 110, 116, 101, 103, 114, 105, 116, 121] The SHA-256 hash of this value, which is the round 1 hash output, is: [218, 24, 160, 17, 160, 50, 235, 35, 216, 209, 100, 174, 155, 163, 10, 117, 180, 111, 172, 200, 127, 201, 206, 173, 40, 45, 58, 170, 35, 93, 9, 60] Given that 256 bits are needed for the CIK and the hash has produced 256 bits, the CIK value is that same value: [218, 24, 160, 17, 160, 50, 235, 35, 216, 209, 100, 174, 155, 163, 10, 117, 180, 111, 172, 200, 127, 201, 206, 173, 40, 45, 58, 170, 35, 93, 9, 60] Jones, et al. Expires June 30, 2013 [Page 43] Internet-Draft JWE December 2012 A.5. Example Key Derivation for "enc" value "A256CBC+HS512" This example uses the Concat KDF to derive the Content Encryption Key (CEK) and Content Integrity Key (CIK) from the Content Master Key (CMK) in the manner described in Section 4.8.1 of [JWA]. In this example, a 512 bit CMK is used to derive a 256 bit CEK and a 512 bit CIK. The CMK value used is: [148, 116, 199, 126, 2, 117, 233, 76, 150, 149, 89, 193, 61, 34, 239, 226, 109, 71, 59, 160, 192, 140, 150, 235, 106, 204, 49, 176, 68, 119, 13, 34, 49, 19, 41, 69, 5, 20, 252, 145, 104, 129, 137, 138, 67, 23, 153, 83, 81, 234, 82, 247, 48, 211, 41, 130, 35, 124, 45, 156, 249, 7, 225, 168] A.5.1. CEK Generation These values are concatenated to produce the round 1 hash input: o the round number 1 as a 32 bit big endian integer ([0, 0, 0, 1]), o the CMK value (as above), o the output bit size 256 as a 32 bit big endian number ([0, 0, 1, 0]), o the bytes of the UTF-8 representation of the "enc" value "A256CBC+HS512" -- [65, 50, 53, 54, 67, 66, 67, 43, 72, 83, 53, 49, 50], o the Datalen value of zero for the omitted "epu" (encryption PartyUInfo) value ([0, 0, 0, 0]), o the Datalen value of zero for the omitted "epv" (encryption PartyVInfo) value ([0, 0, 0, 0]), o the bytes of the ASCII representation of the label "Encryption" -- [69, 110, 99, 114, 121, 112, 116, 105, 111, 110]. Thus the round 1 hash input is: [0, 0, 0, 1, 148, 116, 199, 126, 2, 117, 233, 76, 150, 149, 89, 193, 61, 34, 239, 226, 109, 71, 59, 160, 192, 140, 150, 235, 106, 204, 49, 176, 68, 119, 13, 34, 49, 19, 41, 69, 5, 20, 252, 145, 104, 129, 137, 138, 67, 23, 153, 83, 81, 234, 82, 247, 48, 211, 41, 130, 35, 124, 45, 156, 249, 7, 225, 168, 0, 0, 1, 0, 65, 50, 53, 54, 67, 66, 67, 43, 72, 83, 53, 49, 50, 0, 0, 0, 0, 0, 0, 0, 0, 69, 110, 99, 114, Jones, et al. Expires June 30, 2013 [Page 44] Internet-Draft JWE December 2012 121, 112, 116, 105, 111, 110] The SHA-512 hash of this value, which is the round 1 hash output, is: [157, 19, 75, 205, 31, 190, 110, 46, 117, 217, 137, 19, 116, 166, 126, 60, 18, 244, 226, 114, 38, 153, 78, 198, 26, 0, 181, 168, 113, 45, 149, 89, 107, 213, 109, 183, 207, 164, 86, 131, 51, 105, 214, 29, 229, 32, 243, 46, 40, 53, 123, 4, 13, 7, 250, 48, 227, 207, 167, 211, 147, 91, 0, 171] Given that 256 bits are needed for the CEK and the hash has produced 512 bits, the CEK value is the first 256 bits of that value: [157, 19, 75, 205, 31, 190, 110, 46, 117, 217, 137, 19, 116, 166, 126, 60, 18, 244, 226, 114, 38, 153, 78, 198, 26, 0, 181, 168, 113, 45, 149, 89] A.5.2. CIK Generation These values are concatenated to produce the round 1 hash input: o the round number 1 as a 32 bit big endian integer ([0, 0, 0, 1]), o the CMK value (as above), o the output bit size 512 as a 32 bit big endian number ([0, 0, 2, 0]), o the bytes of the UTF-8 representation of the "enc" value "A256CBC+HS512" -- [65, 50, 53, 54, 67, 66, 67, 43, 72, 83, 53, 49, 50], o the Datalen value of zero for the omitted "epu" (encryption PartyUInfo) value ([0, 0, 0, 0]), o the Datalen value of zero for the omitted "epv" (encryption PartyVInfo) value ([0, 0, 0, 0]), o the bytes of the ASCII representation of the label "Integrity" -- [73, 110, 116, 101, 103, 114, 105, 116, 121]. Thus the round 1 hash input is: [0, 0, 0, 1, 148, 116, 199, 126, 2, 117, 233, 76, 150, 149, 89, 193, 61, 34, 239, 226, 109, 71, 59, 160, 192, 140, 150, 235, 106, 204, 49, 176, 68, 119, 13, 34, 49, 19, 41, 69, 5, 20, 252, 145, 104, 129, 137, 138, 67, 23, 153, 83, 81, 234, 82, 247, 48, 211, 41, 130, 35, 124, 45, 156, 249, 7, 225, 168, 0, 0, 2, 0, 65, 50, 53, 54, 67, 66, 67, Jones, et al. Expires June 30, 2013 [Page 45] Internet-Draft JWE December 2012 43, 72, 83, 53, 49, 50, 0, 0, 0, 0, 0, 0, 0, 0, 73, 110, 116, 101, 103, 114, 105, 116, 121] The SHA-512 hash of this value, which is the round 1 hash output, is: [81, 249, 131, 194, 25, 166, 147, 155, 47, 249, 146, 160, 200, 236, 115, 72, 103, 248, 228, 30, 130, 225, 164, 61, 105, 172, 198, 31, 137, 170, 215, 141, 27, 247, 73, 236, 125, 113, 151, 33, 0, 251, 72, 53, 72, 63, 146, 117, 247, 13, 49, 20, 210, 169, 232, 156, 118, 1, 16, 45, 29, 21, 15, 208] Given that 512 bits are needed for the CIK and the hash has produced 512 bits, the CIK value is that same value: [81, 249, 131, 194, 25, 166, 147, 155, 47, 249, 146, 160, 200, 236, 115, 72, 103, 248, 228, 30, 130, 225, 164, 61, 105, 172, 198, 31, 137, 170, 215, 141, 27, 247, 73, 236, 125, 113, 151, 33, 0, 251, 72, 53, 72, 63, 146, 117, 247, 13, 49, 20, 210, 169, 232, 156, 118, 1, 16, 45, 29, 21, 15, 208] Appendix B. Acknowledgements Solutions for encrypting JSON content were also explored by JSON Simple Encryption [JSE] and JavaScript Message Security Format [I-D.rescorla-jsms], both of which significantly influenced this draft. This draft attempts to explicitly reuse as many of the relevant concepts from XML Encryption 1.1 [W3C.CR-xmlenc-core1-20120313] and RFC 5652 [RFC5652] as possible, while utilizing simple compact JSON-based data structures. Special thanks are due to John Bradley and Nat Sakimura for the discussions that helped inform the content of this specification and to Eric Rescorla and Joe Hildebrand for allowing the reuse of text from [I-D.rescorla-jsms] in this document. Thanks to Axel Nennker, Emmanuel Raviart, Brian Campbell, and Edmund Jay for validating the examples in this specification. This specification is the work of the JOSE Working Group, which includes dozens of active and dedicated participants. In particular, the following individuals contributed ideas, feedback, and wording that influenced this specification: Richard Barnes, John Bradley, Brian Campbell, Breno de Medeiros, Dick Hardt, Jeff Hodges, Edmund Jay, James Manger, Tony Nadalin, Axel Nennker, Emmanuel Raviart, Nat Sakimura, Jim Schaad, Hannes Tschofenig, and Sean Turner. Jones, et al. Expires June 30, 2013 [Page 46] Internet-Draft JWE December 2012 Jim Schaad and Karen O'Donoghue chaired the JOSE working group and Sean Turner and Stephen Farrell served as Security area directors during the creation of this specification. Appendix C. 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 all header fields continue to be required to be understood by implementations using them or should a means of declaring that specific header fields may be safely ignored if not understood should be defined? Appendix D. Document History [[ to be removed by the RFC editor before publication as an RFC ]] -08 o Replaced uses of the term "AEAD" with "Authenticated Encryption", since the term AEAD in the RFC 5116 sense implied the use of a particular data representation, rather than just referring to the class of algorithms that perform authenticated encryption with associated data. o Applied editorial improvements suggested by Jeff Hodges and Hannes Tschofenig. Many of these simplified the terminology used. o Clarified statements of the form "This header parameter is OPTIONAL" to "Use of this header parameter is OPTIONAL". o Added a Header Parameter Usage Location(s) field to the IANA JSON Web Signature and Encryption Header Parameters registry. o Added seriesInfo information to Internet Draft references. -07 o Added a data length prefix to PartyUInfo and PartyVInfo values. o Updated values for example AES CBC calculations. o Made several local editorial changes to clean up loose ends left over from to the decision to only support block encryption methods Jones, et al. Expires June 30, 2013 [Page 47] Internet-Draft JWE December 2012 providing integrity. One of these changes was to explicitly state that the "enc" (encryption method) algorithm must be an Authenticated Encryption algorithm with a specified key length. -06 o Removed the "int" and "kdf" parameters and defined the new composite Authenticated Encryption algorithms "A128CBC+HS256" and "A256CBC+HS512" to replace the former uses of AES CBC, which required the use of separate integrity and key derivation functions. o Included additional values in the Concat KDF calculation -- the desired output size and the algorithm value, and optionally PartyUInfo and PartyVInfo values. Added the optional header parameters "apu" (agreement PartyUInfo), "apv" (agreement PartyVInfo), "epu" (encryption PartyUInfo), and "epv" (encryption PartyVInfo). Updated the KDF examples accordingly. o Promoted Initialization Vector from being a header parameter to being a top-level JWE element. This saves approximately 16 bytes in the compact serialization, which is a significant savings for some use cases. Promoting the Initialization Vector out of the header also avoids repeating this shared value in the JSON serialization. o Changed "x5c" (X.509 Certificate Chain) representation from being a single string to being an array of strings, each containing a single base64 encoded DER certificate value, representing elements of the certificate chain. o Added an AES Key Wrap example. o Reordered the encryption steps so CMK creation is first, when required. o Correct statements in examples about which algorithms produce reproducible results. -05 o Support both direct encryption using a shared or agreed upon symmetric key, and the use of a shared or agreed upon symmetric key to key wrap the CMK. o Added statement that "StringOrURI values are compared as case- sensitive strings with no transformations or canonicalizations applied". Jones, et al. Expires June 30, 2013 [Page 48] Internet-Draft JWE December 2012 o Updated open issues. o Indented artwork elements to better distinguish them from the body text. -04 o Refer to the registries as the primary sources of defined values and then secondarily reference the sections defining the initial contents of the registries. o Normatively reference XML Encryption 1.1 [W3C.CR-xmlenc-core1-20120313] for its security considerations. o Reference draft-jones-jose-jwe-json-serialization instead of draft-jones-json-web-encryption-json-serialization. o Described additional open issues. o Applied editorial suggestions. -03 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 Reordered encryption steps so that the Encoded JWE Header is always created before it is needed as an input to the Authenticated Encryption "additional authenticated data" parameter. o Added the "cty" (content type) header parameter for declaring type information about the secured content, as opposed to the "typ" (type) header parameter, which declares type information about this object. o Moved description of how to determine whether a header is for a JWS or a JWE from the JWT spec to the JWE spec. o Added complete encryption examples for both Authenticated Encryption and non-Authenticated Encryption algorithms. o Added complete key derivation examples. o Added "Collision Resistant Namespace" to the terminology section. Jones, et al. Expires June 30, 2013 [Page 49] Internet-Draft JWE December 2012 o Reference ITU.X690.1994 for DER encoding. o Added Registry Contents sections to populate registry values. o Numerous editorial improvements. -02 o When using Authenticated Encryption algorithms (such as 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 KDF output key sizes. o Generalized text to allow key agreement to be employed as an alternative to key wrapping or key encryption. o Changed compression algorithm from gzip to DEFLATE. o Clarified that it is an error when a "kid" value is included and no matching key is found. o Clarified that JWEs with duplicate Header Parameter Names MUST be rejected. o Clarified the relationship between "typ" header parameter values and MIME types. o Registered application/jwe MIME type and "JWE" typ header parameter value. o Simplified JWK terminology to get replace the "JWK Key Object" and "JWK Container Object" terms with simply "JSON Web Key (JWK)" and "JSON Web Key Set (JWK Set)" and to eliminate potential confusion between single keys and sets of keys. As part of this change, the Header Parameter Name for a public key value was changed from "jpk" (JSON Public Key) to "jwk" (JSON Web Key). o Added suggestion on defining additional header parameters such as "x5t#S256" in the future for certificate thumbprints using hash algorithms other than SHA-1. o Specify RFC 2818 server identity validation, rather than RFC 6125 (paralleling the same decision in the OAuth specs). Jones, et al. Expires June 30, 2013 [Page 50] Internet-Draft JWE December 2012 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 Reformatted to give each header parameter its own section heading. -01 o Added an integrity check for non-Authenticated Encryption algorithms. o Added "jpk" and "x5c" header parameters for including JWK public keys and X.509 certificate chains directly in the header. o Clarified that this specification is defining the JWE Compact Serialization. Referenced the new JWE-JS spec, which defines the JWE JSON Serialization. o Added text "New header parameters should be introduced sparingly since an implementation that does not understand a parameter MUST reject the JWE". o Clarified that the order of the encryption and decryption steps is not significant in cases where there are no dependencies between the inputs and outputs of the steps. o Made other editorial improvements suggested by JOSE working group participants. -00 o Created the initial IETF draft based upon draft-jones-json-web-encryption-02 with no normative changes. o Changed terminology to no longer call both digital signatures and HMACs "signatures". Authors' Addresses Michael B. Jones Microsoft Email: mbj@microsoft.com URI: http://self-issued.info/ Jones, et al. Expires June 30, 2013 [Page 51] Internet-Draft JWE December 2012 Eric Rescorla RTFM, Inc. Email: ekr@rtfm.com Joe Hildebrand Cisco Systems, Inc. Email: jhildebr@cisco.com Jones, et al. 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