| JOSE Working Group | M. Jones |
| Internet-Draft | Microsoft |
| Intended status: Standards Track | J. Hildebrand |
| Expires: December 22, 2014 | Cisco |
| June 20, 2014 |
JSON Web Encryption (JWE)
draft-ietf-jose-json-web-encryption-28
JSON Web Encryption (JWE) represents encrypted content using JavaScript Object Notation (JSON) based data structures. Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) specification and IANA registries defined by that specification. Related digital signature and MAC capabilities are described in the separate JSON Web Signature (JWS) specification.
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Copyright (c) 2014 IETF Trust and the persons identified as the document authors. All rights reserved.
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JSON Web Encryption (JWE) represents encrypted content using JavaScript Object Notation (JSON) [RFC7159] based data structures. The JWE cryptographic mechanisms encrypt and provide integrity protection for an arbitrary sequence of octets.
Two closely related serializations for JWE objects are defined. The JWE Compact Serialization is a compact, URL-safe representation intended for space constrained environments such as HTTP Authorization headers and URI query parameters. The JWE JSON Serialization represents JWE objects as JSON objects and enables the same content to be encrypted to multiple parties. Both share the same cryptographic underpinnings.
Cryptographic algorithms and identifiers for use with this specification are described in the separate JSON Web Algorithms (JWA) [JWA] specification and IANA registries defined by that specification. Related digital signature and MAC capabilities are described in the separate JSON Web Signature (JWS) [JWS] specification.
Names defined by this specification are short because a core goal is for the resulting representations to be compact.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "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]. If these words are used without being spelled in uppercase then they are to be interpreted with their normal natural language meanings.
BASE64URL(OCTETS) denotes the base64url encoding of OCTETS, per Section 2.
UTF8(STRING) denotes the octets of the UTF-8 [RFC3629] representation of STRING.
ASCII(STRING) denotes the octets of the ASCII [USASCII] representation of STRING.
The concatenation of two values A and B is denoted as A || B.
These terms defined by the JSON Web Signature (JWS) [JWS] specification are incorporated into this specification: "JSON Web Signature (JWS)", "Base64url Encoding", "Collision-Resistant Name", and "StringOrURI".
These terms are defined for use by this specification:
JWE represents encrypted content using JSON data structures and base64url encoding. A JWE represents these logical values:
The JWE Header represents the combination of these logical values:
This document defines two serializations for JWE objects: a compact, URL-safe serialization called the JWE Compact Serialization and a JSON serialization called the JWE JSON Serialization. In both serializations, the JWE Protected Header, JWE Encrypted Key, JWE Initialization Vector, JWE Ciphertext, and JWE Authentication Tag are base64url encoded for transmission, since JSON lacks a way to directly represent octet sequences. When present, the JWE AAD is also base64url encoded for transmission.
In the JWE Compact Serialization, no JWE Shared Unprotected Header or JWE Per-Recipient Unprotected Header are used. In this case, the JWE Header and the JWE Protected Header are the same.
In the JWE Compact Serialization, a JWE object is represented as the combination of these five string values,
In the JWE JSON Serialization, one or more of the JWE Protected Header, JWE Shared Unprotected Header, and JWE Per-Recipient Unprotected Header MUST be present. In this case, the members of the JWE Header are the combination of the members of the JWE Protected Header, JWE Shared Unprotected Header, and JWE Per-Recipient Unprotected Header values that are present.
In the JWE JSON Serialization, a JWE object is represented as the combination of these eight values, Section 7.2 for more information about the JWE JSON Serialization.
JWE utilizes authenticated encryption to ensure the confidentiality and integrity of the Plaintext and the integrity of the JWE Protected Header and the JWE AAD.
This example encrypts the plaintext "The true sign of intelligence is not knowledge but imagination." to the recipient using RSAES OAEP for key encryption and AES GCM for content encryption.
The following example JWE Protected Header declares that:
{"alg":"RSA-OAEP","enc":"A256GCM"}
Encoding this JWE Protected Header as BASE64URL(UTF8(JWE Protected Header)) gives this value:
eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ
The remaining steps to finish creating this JWE are:
The final result in this example (with line breaks for display purposes only) is:
eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ. OKOawDo13gRp2ojaHV7LFpZcgV7T6DVZKTyKOMTYUmKoTCVJRgckCL9kiMT03JGe ipsEdY3mx_etLbbWSrFr05kLzcSr4qKAq7YN7e9jwQRb23nfa6c9d-StnImGyFDb Sv04uVuxIp5Zms1gNxKKK2Da14B8S4rzVRltdYwam_lDp5XnZAYpQdb76FdIKLaV mqgfwX7XWRxv2322i-vDxRfqNzo_tETKzpVLzfiwQyeyPGLBIO56YJ7eObdv0je8 1860ppamavo35UgoRdbYaBcoh9QcfylQr66oc6vFWXRcZ_ZT2LawVCWTIy3brGPi 6UklfCpIMfIjf7iGdXKHzg. 48V1_ALb6US04U3b. 5eym8TW_c8SuK0ltJ3rpYIzOeDQz7TALvtu6UG9oMo4vpzs9tX_EFShS8iB7j6ji SdiwkIr3ajwQzaBtQD_A. XFBoMYUZodetZdvTiFvSkQ
See Appendix A.1 for the complete details of computing this JWE. See other parts of Appendix A for additional examples.
The members of the JSON object(s) representing the JWE Header describe the encryption applied to the Plaintext and optionally additional properties of the JWE. The Header Parameter names within the JWE Header MUST be unique; recipients MUST either reject JWEs with duplicate Header Parameter names or use a JSON parser that returns only the lexically last duplicate member name, as specified in Section 15.12 (The JSON Object) of ECMAScript 5.1 [ECMAScript].
Implementations are required to understand the specific Header Parameters defined by this specification that are designated as "MUST be understood" and process them in the manner defined in this specification. All other Header Parameters defined by this specification that are not so designated MUST be ignored when not understood. Unless listed as a critical Header Parameter, per Section 4.1.13, all Header Parameters not defined by this specification MUST be ignored when not understood.
There are three classes of Header Parameter names: Registered Header Parameter names, Public Header Parameter names, and Private Header Parameter names.
The following Header Parameter names are registered in the IANA JSON Web Signature and Encryption Header Parameters registry defined in [JWS], with meanings as defined below.
As indicated by the common registry, JWSs and JWEs share a common Header Parameter space; when a parameter is used by both specifications, its usage must be compatible between the specifications.
This parameter has the same meaning, syntax, and processing rules as the alg Header Parameter defined in Section 4.1.1 of [JWS], except that the Header Parameter identifies the cryptographic algorithm used to encrypt or determine the value of the Content Encryption Key (CEK). The encrypted content is not usable if the alg value does not represent a supported algorithm, or if the recipient does not have a key that can be used with that algorithm.
A list of defined alg values for this use can be found in the IANA JSON Web Signature and Encryption Algorithms registry defined in [JWA]; the initial contents of this registry are the values defined in Section 4.1 of the JSON Web Algorithms (JWA) [JWA] specification.
The enc (encryption algorithm) Header Parameter identifies the content encryption algorithm used to encrypt the Plaintext to produce the Ciphertext. This algorithm MUST be an AEAD algorithm with a specified key length. The recipient MUST reject the JWE if the enc value does not represent a supported algorithm. enc values should either be registered in the IANA JSON Web Signature and Encryption Algorithms registry defined in [JWA] or be a value that contains a Collision-Resistant Name. The enc value is a case-sensitive string containing a StringOrURI value. This Header Parameter MUST be present and MUST be understood and processed by implementations.
A list of defined enc values for this use can be found in the IANA JSON Web Signature and Encryption Algorithms registry defined in [JWA]; the initial contents of this registry are the values defined in Section 5.1 of the JSON Web Algorithms (JWA) [JWA] specification.
The zip (compression algorithm) applied to the Plaintext before encryption, if any. The zip value defined by this specification is:
Other values MAY be used. Compression algorithm values can be registered in the IANA JSON Web Encryption Compression Algorithm registry defined in [JWA]. The zip value is a case-sensitive string. If no zip parameter is present, no compression is applied to the Plaintext before encryption. This Header Parameter MUST be integrity protected, and therefore MUST occur only within the JWE Protected Header, when used. Use of this Header Parameter is OPTIONAL. This Header Parameter MUST be understood and processed by implementations.
This parameter has the same meaning, syntax, and processing rules as the jku Header Parameter defined in Section 4.1.2 of [JWS], except that the JWK Set resource contains the public key to which the JWE was encrypted; this can be used to determine the private key needed to decrypt the JWE.
This parameter has the same meaning, syntax, and processing rules as the jwk Header Parameter defined in Section 4.1.3 of [JWS], except that the key is the public key to which the JWE was encrypted; this can be used to determine the private key needed to decrypt the JWE.
This parameter has the same meaning, syntax, and processing rules as the kid Header Parameter defined in Section 4.1.4 of [JWS], except that the key hint references the public key to which the JWE was encrypted; 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 JWE recipients.
This parameter has the same meaning, syntax, and processing rules as the x5u Header Parameter defined in Section 4.1.5 of [JWS], except that the X.509 public key certificate or certificate chain [RFC5280] contains the public key to which the JWE was encrypted; this can be used to determine the private key needed to decrypt the JWE.
This parameter has the same meaning, syntax, and processing rules as the x5c Header Parameter defined in Section 4.1.6 of [JWS], except that the X.509 public key certificate or certificate chain [RFC5280] contains the public key to which the JWE was encrypted; this can be used to determine the private key needed to decrypt the JWE.
See Appendix B of [JWS] for an example x5c value.
This parameter has the same meaning, syntax, and processing rules as the x5t Header Parameter defined in Section 4.1.7 of [JWS], except that the certificate referenced by the thumbprint contains the public key to which the JWE was encrypted; this can be used to determine the private key needed to decrypt the JWE.
This parameter has the same meaning, syntax, and processing rules as the x5t#S256 Header Parameter defined in Section 4.1.8 of [JWS], except that the certificate referenced by the thumbprint contains the public key to which the JWE was encrypted; this can be used to determine the private key needed to decrypt the JWE.
This parameter has the same meaning, syntax, and processing rules as the typ Header Parameter defined in Section 4.1.9 of [JWS], except that the type is that of this complete JWE object.
This parameter has the same meaning, syntax, and processing rules as the cty Header Parameter defined in Section 4.1.10 of [JWS], except that the type is that of the secured content (the plaintext).
This parameter has the same meaning, syntax, and processing rules as the crit Header Parameter defined in Section 4.1.11 of [JWS], except that JWE Header Parameters are being referred to, rather than JWS Header Parameters.
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 defined in [JWS] or be a Public Name: a value that contains a Collision-Resistant Name. 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.
A producer and consumer of a JWE may agree to use Header Parameter names that are Private Names: names that are not Registered Header Parameter names Section 4.1 or Public Header Parameter names Section 4.2. Unlike Public Header Parameter names, Private Header Parameter names are subject to collision and should be used with caution.
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.
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 encrypted content cannot be validated.
It is an application decision which recipients' encrypted content must successfully validate for the JWE to be accepted. In some cases, encrypted content for all recipients must successfully validate or the JWE will be rejected. In other cases, only the encrypted content for a single recipient needs to be successfully validated. However, in all cases, the encrypted content for at least one recipient MUST successfully validate or the JWE MUST be rejected.
The string comparison rules for this specification are the same as those defined in Section 5.3 of [JWS].
The key identification methods for this specification are the same as those defined in Section 6 of [JWS], except that the key being identified is the public key to which the JWE was encrypted.
JWE objects use one of two serializations, the JWE Compact Serialization or the JWE JSON Serialization. Applications using this specification need to specify what serialization and serialization features are used for that application. For instance, applications might specify that only the JWE JSON Serialization is used, that only JWE JSON Serialization support for a single recipient is used, or that support for multiple recipients is used. JWE implementations only need to implement the features needed for the applications they are designed to support.
The JWE Compact Serialization represents encrypted content as a compact URL-safe string. This string is BASE64URL(UTF8(JWE Protected Header)) || '.' || BASE64URL(JWE Encrypted Key) || '.' || BASE64URL(JWE Initialization Vector) || '.' || BASE64URL(JWE Ciphertext) || '.' || BASE64URL(JWE Authentication Tag). Only one recipient is supported by the JWE Compact Serialization and it provides no syntax to represent JWE Shared Unprotected Header, JWE Per-Recipient Unprotected Header, or JWE AAD values.
The JWE JSON Serialization represents encrypted content as a JSON object. Content using the JWE JSON Serialization can be encrypted to more than one recipient. This representation is neither optimized for compactness nor URL-safe.
The following members are defined for use in top-level JSON objects used for the JWE JSON Serialization:
The following members are defined for use in the JSON objects that are elements of the recipients array:
At least one of the header, protected, and unprotected members MUST be present so that alg and enc Header Parameter values are conveyed for each recipient computation.
Additional members can be present in both the JSON objects defined above; if not understood by implementations encountering them, they MUST be ignored.
Some Header Parameters, including the alg parameter, can be shared among all recipient computations. Header Parameters in the JWE Protected Header and JWE Shared Unprotected Header values are shared among all recipients.
The Header Parameter values used when creating or validating per-recipient Ciphertext and Authentication Tag values are the union of the three sets of Header Parameter values that may be present: (1) the JWE Protected Header represented in the protected member, (2) the JWE Shared Unprotected Header represented in the unprotected member, and (3) the JWE Per-Recipient Unprotected Header represented in the header member of the recipient's array element. The union of these sets of Header Parameters comprises the JWE Header. The Header Parameter names in the three locations MUST be disjoint.
Each JWE Encrypted Key value is computed using the parameters of the corresponding JWE Header value in the same manner as for the JWE Compact Serialization. This has the desirable property that each JWE Encrypted Key value in the recipients array is identical to the value that would have been computed for the same parameter in the JWE Compact Serialization. Likewise, the JWE Ciphertext and JWE Authentication Tag values match those produced for the JWE Compact Serialization, provided that the JWE Protected Header value (which represents the integrity-protected Header Parameter values) matches that used in the JWE Compact Serialization.
All recipients use the same JWE Protected Header, JWE Initialization Vector, JWE Ciphertext, and JWE Authentication Tag values, when present, resulting in potentially significant space savings if the message is large. Therefore, all Header Parameters that specify the treatment of the Plaintext value MUST be the same for all recipients. This primarily means that the enc (encryption algorithm) Header Parameter value in the JWE Header for each recipient and any parameters of that algorithm MUST be the same.
In summary, the syntax of a JWE using the JWE JSON Serialization is as follows:
{"protected":"<integrity-protected shared header contents>",
"unprotected":<non-integrity-protected shared header contents>,
"recipients":[
{"header":<per-recipient unprotected header 1 contents>,
"encrypted_key":"<encrypted key 1 contents>"},
...
{"header":<per-recipient unprotected header N contents>,
"encrypted_key":"<encrypted key N contents>"}],
"aad":"<additional authenticated data contents>",
"iv":"<initialization vector contents>",
"ciphertext":"<ciphertext contents>",
"tag":"<authentication tag contents>"
}
See Appendix A.4 for an example of computing a JWE using the JWE JSON Serialization.
The TLS requirements for this specification are the same as those defined in Section 8 of [JWS].
There are several ways of distinguishing whether an object is a JWS or JWE object. All these methods will yield the same result for all legal input values; they may yield different results for malformed inputs.
This specification registers the Header Parameter names defined in Section 4.1 in the IANA JSON Web Signature and Encryption Header Parameters registry defined in [JWS].
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 asymmetric private and symmetric secret keys, preventing various attacks, and helping avoid mistakes such as inadvertently encrypting a message to 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.REC-xmlenc-core1-20130411] also apply, other than those that are XML specific.
Algorithms of matching strengths should be used together whenever possible. For instance, when AES Key Wrap is used with a given key size, using the same key size is recommended when AES GCM is also used.
When decrypting, particular care must be taken not to allow the JWE recipient to be used as an oracle for decrypting messages. RFC 3218 [RFC3218] should be consulted for specific countermeasures to attacks on RSAES-PKCS1-V1_5. An attacker might modify the contents of the alg parameter from RSA-OAEP to RSA1_5 in order to generate a formatting error that can be detected and used to recover the CEK even if RSAES OAEP was used to encrypt the CEK. It is therefore particularly important to report all formatting errors to the CEK, Additional Authenticated Data, or ciphertext as a single error when the encrypted content is rejected.
Additionally, this type of attack can be prevented by the use of "key tainting". This method restricts the use of a key to a limited set of algorithms -- usually one. This means, for instance, that if the key is marked as being for RSA-OAEP only, any attempt to decrypt a message using the RSA1_5 algorithm with that key would fail immediately due to invalid use of the key.
To mitigate the attacks described in RFC 3218 [RFC3218], the recipient MUST NOT distinguish between format, padding, and length errors of encrypted keys. It is strongly recommended, in the event of receiving an improperly formatted key, that the receiver substitute a randomly generated CEK and proceed to the next step, to mitigate timing attacks.
| [I-D.mcgrew-aead-aes-cbc-hmac-sha2] | McGrew, D., Foley, J. and K. Paterson, "Authenticated Encryption with AES-CBC and HMAC-SHA", Internet-Draft draft-mcgrew-aead-aes-cbc-hmac-sha2-04, February 2014. |
| [I-D.rescorla-jsms] | Rescorla, E. and J. Hildebrand, "JavaScript Message Security Format", Internet-Draft draft-rescorla-jsms-00, March 2011. |
| [JSE] | Bradley, J. and N. Sakimura (editor), "JSON Simple Encryption", September 2010. |
| [RFC3218] | Rescorla, E., "Preventing the Million Message Attack on Cryptographic Message Syntax", RFC 3218, January 2002. |
| [RFC4086] | Eastlake, D., Schiller, J. and S. Crocker, "Randomness Requirements for Security", BCP 106, RFC 4086, June 2005. |
| [RFC5652] | Housley, R., "Cryptographic Message Syntax (CMS)", STD 70, RFC 5652, September 2009. |
| [W3C.REC-xmlenc-core1-20130411] | Eastlake, D., Reagle, J., Hirsch, F. and T. Roessler, "XML Encryption Syntax and Processing Version 1.1", World Wide Web Consortium Recommendation REC-xmlenc-core1-20130411, April 2013. |
This section provides examples of JWE computations.
This example encrypts the plaintext "The true sign of intelligence is not knowledge but imagination." to the recipient using RSAES OAEP for key encryption and AES GCM for content encryption. The representation of this plaintext (using JSON array notation) 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]
The following example JWE Protected Header declares that:
{"alg":"RSA-OAEP","enc":"A256GCM"}
Encoding this JWE Protected Header as BASE64URL(UTF8(JWE Protected Header)) gives this value:
eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ
Generate a 256 bit random Content Encryption Key (CEK). In this example, the value (using JSON array notation) 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]
Encrypt the CEK with the recipient's public key using the RSAES OAEP algorithm to produce the JWE Encrypted Key. This example uses the RSA key represented in JSON Web Key [JWK] format below (with line breaks for display purposes only):
{"kty":"RSA",
"n":"oahUIoWw0K0usKNuOR6H4wkf4oBUXHTxRvgb48E-BVvxkeDNjbC4he8rUW
cJoZmds2h7M70imEVhRU5djINXtqllXI4DFqcI1DgjT9LewND8MW2Krf3S
psk_ZkoFnilakGygTwpZ3uesH-PFABNIUYpOiN15dsQRkgr0vEhxN92i2a
sbOenSZeyaxziK72UwxrrKoExv6kc5twXTq4h-QChLOln0_mtUZwfsRaMS
tPs6mS6XrgxnxbWhojf663tuEQueGC-FCMfra36C9knDFGzKsNa7LZK2dj
YgyD3JR_MB_4NUJW_TqOQtwHYbxevoJArm-L5StowjzGy-_bq6Gw",
"e":"AQAB",
"d":"kLdtIj6GbDks_ApCSTYQtelcNttlKiOyPzMrXHeI-yk1F7-kpDxY4-WY5N
WV5KntaEeXS1j82E375xxhWMHXyvjYecPT9fpwR_M9gV8n9Hrh2anTpTD9
3Dt62ypW3yDsJzBnTnrYu1iwWRgBKrEYY46qAZIrA2xAwnm2X7uGR1hghk
qDp0Vqj3kbSCz1XyfCs6_LehBwtxHIyh8Ripy40p24moOAbgxVw3rxT_vl
t3UVe4WO3JkJOzlpUf-KTVI2Ptgm-dARxTEtE-id-4OJr0h-K-VFs3VSnd
VTIznSxfyrj8ILL6MG_Uv8YAu7VILSB3lOW085-4qE3DzgrTjgyQ"
}
The resulting JWE Encrypted Key value is:
[56, 163, 154, 192, 58, 53, 222, 4, 105, 218, 136, 218, 29, 94, 203, 22, 150, 92, 129, 94, 211, 232, 53, 89, 41, 60, 138, 56, 196, 216, 82, 98, 168, 76, 37, 73, 70, 7, 36, 8, 191, 100, 136, 196, 244, 220, 145, 158, 138, 155, 4, 117, 141, 230, 199, 247, 173, 45, 182, 214, 74, 177, 107, 211, 153, 11, 205, 196, 171, 226, 162, 128, 171, 182, 13, 237, 239, 99, 193, 4, 91, 219, 121, 223, 107, 167, 61, 119, 228, 173, 156, 137, 134, 200, 80, 219, 74, 253, 56, 185, 91, 177, 34, 158, 89, 154, 205, 96, 55, 18, 138, 43, 96, 218, 215, 128, 124, 75, 138, 243, 85, 25, 109, 117, 140, 26, 155, 249, 67, 167, 149, 231, 100, 6, 41, 65, 214, 251, 232, 87, 72, 40, 182, 149, 154, 168, 31, 193, 126, 215, 89, 28, 111, 219, 125, 182, 139, 235, 195, 197, 23, 234, 55, 58, 63, 180, 68, 202, 206, 149, 75, 205, 248, 176, 67, 39, 178, 60, 98, 193, 32, 238, 122, 96, 158, 222, 57, 183, 111, 210, 55, 188, 215, 206, 180, 166, 150, 166, 106, 250, 55, 229, 72, 40, 69, 214, 216, 104, 23, 40, 135, 212, 28, 127, 41, 80, 175, 174, 168, 115, 171, 197, 89, 116, 92, 103, 246, 83, 216, 182, 176, 84, 37, 147, 35, 45, 219, 172, 99, 226, 233, 73, 37, 124, 42, 72, 49, 242, 35, 127, 184, 134, 117, 114, 135, 206]
Encoding this JWE Encrypted Key as BASE64URL(JWE Encrypted Key) gives this value (with line breaks for display purposes only):
OKOawDo13gRp2ojaHV7LFpZcgV7T6DVZKTyKOMTYUmKoTCVJRgckCL9kiMT03JGe ipsEdY3mx_etLbbWSrFr05kLzcSr4qKAq7YN7e9jwQRb23nfa6c9d-StnImGyFDb Sv04uVuxIp5Zms1gNxKKK2Da14B8S4rzVRltdYwam_lDp5XnZAYpQdb76FdIKLaV mqgfwX7XWRxv2322i-vDxRfqNzo_tETKzpVLzfiwQyeyPGLBIO56YJ7eObdv0je8 1860ppamavo35UgoRdbYaBcoh9QcfylQr66oc6vFWXRcZ_ZT2LawVCWTIy3brGPi 6UklfCpIMfIjf7iGdXKHzg
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]
Encoding this JWE Initialization Vector as BASE64URL(JWE Initialization Vector) gives this value:
48V1_ALb6US04U3b
Let the Additional Authenticated Data encryption parameter be ASCII(BASE64URL(UTF8(JWE Protected Header))). 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]
Encrypt the Plaintext with AES GCM using the CEK 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:
[229, 236, 166, 241, 53, 191, 115, 196, 174, 43, 73, 109, 39, 122, 233, 96, 140, 206, 120, 52, 51, 237, 48, 11, 190, 219, 186, 80, 111, 104, 50, 142, 47, 167, 59, 61, 181, 127, 196, 21, 40, 82, 242, 32, 123, 143, 168, 226, 73, 216, 176, 144, 138, 247, 106, 60, 16, 205, 160, 109, 64, 63, 192]
The resulting Authentication Tag value is:
[92, 80, 104, 49, 133, 25, 161, 215, 173, 101, 219, 211, 136, 91, 210, 145]
Encoding this JWE Ciphertext as BASE64URL(JWE Ciphertext) gives this value (with line breaks for display purposes only):
5eym8TW_c8SuK0ltJ3rpYIzOeDQz7TALvtu6UG9oMo4vpzs9tX_EFShS8iB7j6ji SdiwkIr3ajwQzaBtQD_A
Encoding this JWE Authentication Tag as BASE64URL(JWE Authentication Tag) gives this value:
XFBoMYUZodetZdvTiFvSkQ
Assemble the final representation: The Compact Serialization of this result is the string BASE64URL(UTF8(JWE Protected Header)) || '.' || BASE64URL(JWE Encrypted Key) || '.' || BASE64URL(JWE Initialization Vector) || '.' || BASE64URL(JWE Ciphertext) || '.' || BASE64URL(JWE Authentication Tag).
The final result in this example (with line breaks for display purposes only) is:
eyJhbGciOiJSU0EtT0FFUCIsImVuYyI6IkEyNTZHQ00ifQ. OKOawDo13gRp2ojaHV7LFpZcgV7T6DVZKTyKOMTYUmKoTCVJRgckCL9kiMT03JGe ipsEdY3mx_etLbbWSrFr05kLzcSr4qKAq7YN7e9jwQRb23nfa6c9d-StnImGyFDb Sv04uVuxIp5Zms1gNxKKK2Da14B8S4rzVRltdYwam_lDp5XnZAYpQdb76FdIKLaV mqgfwX7XWRxv2322i-vDxRfqNzo_tETKzpVLzfiwQyeyPGLBIO56YJ7eObdv0je8 1860ppamavo35UgoRdbYaBcoh9QcfylQr66oc6vFWXRcZ_ZT2LawVCWTIy3brGPi 6UklfCpIMfIjf7iGdXKHzg. 48V1_ALb6US04U3b. 5eym8TW_c8SuK0ltJ3rpYIzOeDQz7TALvtu6UG9oMo4vpzs9tX_EFShS8iB7j6ji SdiwkIr3ajwQzaBtQD_A. XFBoMYUZodetZdvTiFvSkQ
This example illustrates the process of creating a JWE with RSAES OAEP for key encryption and AES GCM for content encryption. 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.
This example encrypts the plaintext "Live long and prosper." to the recipient using RSAES-PKCS1-V1_5 for key encryption and AES_128_CBC_HMAC_SHA_256 for content encryption. The representation of this plaintext (using JSON array notation) is:
[76, 105, 118, 101, 32, 108, 111, 110, 103, 32, 97, 110, 100, 32, 112, 114, 111, 115, 112, 101, 114, 46]
The following example JWE Protected Header declares that:
{"alg":"RSA1_5","enc":"A128CBC-HS256"}
Encoding this JWE Protected Header as BASE64URL(UTF8(JWE Protected Header)) gives this value:
eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0
Generate a 256 bit random Content Encryption Key (CEK). 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]
Encrypt the CEK with the recipient's public key using the RSAES-PKCS1-V1_5 algorithm to produce the JWE Encrypted Key. This example uses the RSA key represented in JSON Web Key [JWK] format below (with line breaks for display purposes only):
{"kty":"RSA",
"n":"sXchDaQebHnPiGvyDOAT4saGEUetSyo9MKLOoWFsueri23bOdgWp4Dy1Wl
UzewbgBHod5pcM9H95GQRV3JDXboIRROSBigeC5yjU1hGzHHyXss8UDpre
cbAYxknTcQkhslANGRUZmdTOQ5qTRsLAt6BTYuyvVRdhS8exSZEy_c4gs_
7svlJJQ4H9_NxsiIoLwAEk7-Q3UXERGYw_75IDrGA84-lA_-Ct4eTlXHBI
Y2EaV7t7LjJaynVJCpkv4LKjTTAumiGUIuQhrNhZLuF_RJLqHpM2kgWFLU
7-VTdL1VbC2tejvcI2BlMkEpk1BzBZI0KQB0GaDWFLN-aEAw3vRw",
"e":"AQAB",
"d":"VFCWOqXr8nvZNyaaJLXdnNPXZKRaWCjkU5Q2egQQpTBMwhprMzWzpR8Sxq
1OPThh_J6MUD8Z35wky9b8eEO0pwNS8xlh1lOFRRBoNqDIKVOku0aZb-ry
nq8cxjDTLZQ6Fz7jSjR1Klop-YKaUHc9GsEofQqYruPhzSA-QgajZGPbE_
0ZaVDJHfyd7UUBUKunFMScbflYAAOYJqVIVwaYR5zWEEceUjNnTNo_CVSj
-VvXLO5VZfCUAVLgW4dpf1SrtZjSt34YLsRarSb127reG_DUwg9Ch-Kyvj
T1SkHgUWRVGcyly7uvVGRSDwsXypdrNinPA4jlhoNdizK2zF2CWQ"
}
The resulting JWE Encrypted Key value is:
[80, 104, 72, 58, 11, 130, 236, 139, 132, 189, 255, 205, 61, 86, 151, 176, 99, 40, 44, 233, 176, 189, 205, 70, 202, 169, 72, 40, 226, 181, 156, 223, 120, 156, 115, 232, 150, 209, 145, 133, 104, 112, 237, 156, 116, 250, 65, 102, 212, 210, 103, 240, 177, 61, 93, 40, 71, 231, 223, 226, 240, 157, 15, 31, 150, 89, 200, 215, 198, 203, 108, 70, 117, 66, 212, 238, 193, 205, 23, 161, 169, 218, 243, 203, 128, 214, 127, 253, 215, 139, 43, 17, 135, 103, 179, 220, 28, 2, 212, 206, 131, 158, 128, 66, 62, 240, 78, 186, 141, 125, 132, 227, 60, 137, 43, 31, 152, 199, 54, 72, 34, 212, 115, 11, 152, 101, 70, 42, 219, 233, 142, 66, 151, 250, 126, 146, 141, 216, 190, 73, 50, 177, 146, 5, 52, 247, 28, 197, 21, 59, 170, 247, 181, 89, 131, 241, 169, 182, 246, 99, 15, 36, 102, 166, 182, 172, 197, 136, 230, 120, 60, 58, 219, 243, 149, 94, 222, 150, 154, 194, 110, 227, 225, 112, 39, 89, 233, 112, 207, 211, 241, 124, 174, 69, 221, 179, 107, 196, 225, 127, 167, 112, 226, 12, 242, 16, 24, 28, 120, 182, 244, 213, 244, 153, 194, 162, 69, 160, 244, 248, 63, 165, 141, 4, 207, 249, 193, 79, 131, 0, 169, 233, 127, 167, 101, 151, 125, 56, 112, 111, 248, 29, 232, 90, 29, 147, 110, 169, 146, 114, 165, 204, 71, 136, 41, 252]
Encoding this JWE Encrypted Key as BASE64URL(JWE Encrypted Key) gives this value (with line breaks for display purposes only):
UGhIOguC7IuEvf_NPVaXsGMoLOmwvc1GyqlIKOK1nN94nHPoltGRhWhw7Zx0-kFm 1NJn8LE9XShH59_i8J0PH5ZZyNfGy2xGdULU7sHNF6Gp2vPLgNZ__deLKxGHZ7Pc HALUzoOegEI-8E66jX2E4zyJKx-YxzZIItRzC5hlRirb6Y5Cl_p-ko3YvkkysZIF NPccxRU7qve1WYPxqbb2Yw8kZqa2rMWI5ng8OtvzlV7elprCbuPhcCdZ6XDP0_F8 rkXds2vE4X-ncOIM8hAYHHi29NX0mcKiRaD0-D-ljQTP-cFPgwCp6X-nZZd9OHBv -B3oWh2TbqmScqXMR4gp_A
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]
Encoding this JWE Initialization Vector as BASE64URL(JWE Initialization Vector) gives this value:
AxY8DCtDaGlsbGljb3RoZQ
Let the Additional Authenticated Data encryption parameter be ASCII(BASE64URL(UTF8(JWE Protected Header))). 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, 76, 85, 104, 84, 77, 106, 85, 50, 73, 110, 48]
Encrypt the Plaintext with AES_128_CBC_HMAC_SHA_256 using the CEK as the encryption key, the JWE Initialization Vector, and the Additional Authenticated Data value above. The steps for doing this using the values from Appendix A.3 are detailed in Appendix B. The resulting Ciphertext is:
[40, 57, 83, 181, 119, 33, 133, 148, 198, 185, 243, 24, 152, 230, 6, 75, 129, 223, 127, 19, 210, 82, 183, 230, 168, 33, 215, 104, 143, 112, 56, 102]
The resulting Authentication Tag value is:
[246, 17, 244, 190, 4, 95, 98, 3, 231, 0, 115, 157, 242, 203, 100, 191]
Encoding this JWE Ciphertext as BASE64URL(JWE Ciphertext) gives this value:
KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY
Encoding this JWE Authentication Tag as BASE64URL(JWE Authentication Tag) gives this value:
9hH0vgRfYgPnAHOd8stkvw
Assemble the final representation: The Compact Serialization of this result is the string BASE64URL(UTF8(JWE Protected Header)) || '.' || BASE64URL(JWE Encrypted Key) || '.' || BASE64URL(JWE Initialization Vector) || '.' || BASE64URL(JWE Ciphertext) || '.' || BASE64URL(JWE Authentication Tag).
The final result in this example (with line breaks for display purposes only) is:
eyJhbGciOiJSU0ExXzUiLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0. UGhIOguC7IuEvf_NPVaXsGMoLOmwvc1GyqlIKOK1nN94nHPoltGRhWhw7Zx0-kFm 1NJn8LE9XShH59_i8J0PH5ZZyNfGy2xGdULU7sHNF6Gp2vPLgNZ__deLKxGHZ7Pc HALUzoOegEI-8E66jX2E4zyJKx-YxzZIItRzC5hlRirb6Y5Cl_p-ko3YvkkysZIF NPccxRU7qve1WYPxqbb2Yw8kZqa2rMWI5ng8OtvzlV7elprCbuPhcCdZ6XDP0_F8 rkXds2vE4X-ncOIM8hAYHHi29NX0mcKiRaD0-D-ljQTP-cFPgwCp6X-nZZd9OHBv -B3oWh2TbqmScqXMR4gp_A. AxY8DCtDaGlsbGljb3RoZQ. KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY. 9hH0vgRfYgPnAHOd8stkvw
This example illustrates the process of creating a JWE with RSAES-PKCS1-V1_5 for key encryption and AES_CBC_HMAC_SHA2 for content encryption. 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.
This example encrypts the plaintext "Live long and prosper." to the recipient using AES Key Wrap for key encryption and AES_128_CBC_HMAC_SHA_256 for content encryption. The representation of this plaintext (using JSON array notation) is:
[76, 105, 118, 101, 32, 108, 111, 110, 103, 32, 97, 110, 100, 32, 112, 114, 111, 115, 112, 101, 114, 46]
The following example JWE Protected Header declares that:
{"alg":"A128KW","enc":"A128CBC-HS256"}
Encoding this JWE Protected Header as BASE64URL(UTF8(JWE Protected Header)) gives this value:
eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0
Generate a 256 bit random Content Encryption Key (CEK). In this example, the 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]
Encrypt the CEK with the shared symmetric key using the AES Key Wrap algorithm to produce the JWE Encrypted Key. This example uses the symmetric key represented in JSON Web Key [JWK] format below:
{"kty":"oct",
"k":"GawgguFyGrWKav7AX4VKUg"
}
The resulting JWE Encrypted Key value is:
[232, 160, 123, 211, 183, 76, 245, 132, 200, 128, 123, 75, 190, 216, 22, 67, 201, 138, 193, 186, 9, 91, 122, 31, 246, 90, 28, 139, 57, 3, 76, 124, 193, 11, 98, 37, 173, 61, 104, 57]
Encoding this JWE Encrypted Key as BASE64URL(JWE Encrypted Key) gives this value:
6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ
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]
Encoding this JWE Initialization Vector as BASE64URL(JWE Initialization Vector) gives this value:
AxY8DCtDaGlsbGljb3RoZQ
Let the Additional Authenticated Data encryption parameter be ASCII(BASE64URL(UTF8(JWE Protected Header))). 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, 81, 48, 74, 68, 76, 85, 104, 84, 77, 106, 85, 50, 73, 110, 48]
Encrypt the Plaintext with AES_128_CBC_HMAC_SHA_256 using the CEK as the encryption key, the JWE Initialization Vector, and the Additional Authenticated Data value above. The steps for doing this using the values from this example are detailed in Appendix B. The resulting Ciphertext is:
[40, 57, 83, 181, 119, 33, 133, 148, 198, 185, 243, 24, 152, 230, 6, 75, 129, 223, 127, 19, 210, 82, 183, 230, 168, 33, 215, 104, 143, 112, 56, 102]
The resulting Authentication Tag value is:
[83, 73, 191, 98, 104, 205, 211, 128, 201, 189, 199, 133, 32, 38, 194, 85]
Encoding this JWE Ciphertext as BASE64URL(JWE Ciphertext) gives this value:
KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY
Encoding this JWE Authentication Tag as BASE64URL(JWE Authentication Tag) gives this value:
U0m_YmjN04DJvceFICbCVQ
Assemble the final representation: The Compact Serialization of this result is the string BASE64URL(UTF8(JWE Protected Header)) || '.' || BASE64URL(JWE Encrypted Key) || '.' || BASE64URL(JWE Initialization Vector) || '.' || BASE64URL(JWE Ciphertext) || '.' || BASE64URL(JWE Authentication Tag).
The final result in this example (with line breaks for display purposes only) is:
eyJhbGciOiJBMTI4S1ciLCJlbmMiOiJBMTI4Q0JDLUhTMjU2In0. 6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ. AxY8DCtDaGlsbGljb3RoZQ. KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY. U0m_YmjN04DJvceFICbCVQ
This example illustrates the process of creating a JWE with AES Key Wrap for key encryption and AES GCM for content encryption. 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.
This section contains an example using the JWE JSON Serialization. This example demonstrates the capability for encrypting the same plaintext to multiple recipients.
Two recipients are present in this example. The algorithm and key used for the first recipient are the same as that used in Appendix A.2. The algorithm and key used for the second recipient are the same as that used in Appendix A.3. The resulting JWE Encrypted Key values are therefore the same; those computations are not repeated here.
The Plaintext, the Content Encryption Key (CEK), Initialization Vector, and JWE Protected Header are shared by all recipients (which must be the case, since the Ciphertext and Authentication Tag are also shared).
The first recipient uses the RSAES-PKCS1-V1_5 algorithm to encrypt the Content Encryption Key (CEK). The second uses AES Key Wrap to encrypt the CEK. Key ID values are supplied for both keys. The two per-recipient header values used to represent these algorithms and Key IDs are:
{"alg":"RSA1_5","kid":"2011-04-29"}
and
{"alg":"A128KW","kid":"7"}
The Plaintext is encrypted using the AES_128_CBC_HMAC_SHA_256 algorithm to produce the common JWE Ciphertext and JWE Authentication Tag values. The JWE Protected Header value representing this is:
{"enc":"A128CBC-HS256"}
Encoding this JWE Protected Header as BASE64URL(UTF8(JWE Protected Header)) gives this value:
eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0
This JWE uses the jku Header Parameter to reference a JWK Set. This is represented in the following JWE Unprotected Header value as:
{"jku":"https://server.example.com/keys.jwks"}
Combining the per-recipient, protected, and unprotected header values supplied, the JWE Header values used for the first and second recipient respectively are:
{"alg":"RSA1_5",
"kid":"2011-04-29",
"enc":"A128CBC-HS256",
"jku":"https://server.example.com/keys.jwks"}
and
{"alg":"A128KW",
"kid":"7",
"enc":"A128CBC-HS256",
"jku":"https://server.example.com/keys.jwks"}
Let the Additional Authenticated Data encryption parameter be ASCII(BASE64URL(UTF8(JWE Protected Header))). This value is:
[101, 121, 74, 108, 98, 109, 77, 105, 79, 105, 74, 66, 77, 84, 73, 52, 81, 48, 74, 68, 76, 85, 104, 84, 77, 106, 85, 50, 73, 110, 48]
Encrypt the Plaintext with AES_128_CBC_HMAC_SHA_256 using the CEK as the encryption key, the JWE Initialization Vector, and the Additional Authenticated Data value above. The steps for doing this using the values from Appendix A.3 are detailed in Appendix B. The resulting Ciphertext is:
[40, 57, 83, 181, 119, 33, 133, 148, 198, 185, 243, 24, 152, 230, 6, 75, 129, 223, 127, 19, 210, 82, 183, 230, 168, 33, 215, 104, 143, 112, 56, 102]
The resulting Authentication Tag value is:
[51, 63, 149, 60, 252, 148, 225, 25, 92, 185, 139, 245, 35, 2, 47, 207]
Encoding this JWE Ciphertext as BASE64URL(JWE Ciphertext) gives this value:
KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY
Encoding this JWE Authentication Tag as BASE64URL(JWE Authentication Tag) gives this value:
Mz-VPPyU4RlcuYv1IwIvzw
The complete JSON Web Encryption JSON Serialization for these values is as follows (with line breaks for display purposes only):
{"protected":
"eyJlbmMiOiJBMTI4Q0JDLUhTMjU2In0",
"unprotected":
{"jku":"https://server.example.com/keys.jwks"},
"recipients":[
{"header":
{"alg":"RSA1_5","kid":"2011-04-29"},
"encrypted_key":
"UGhIOguC7IuEvf_NPVaXsGMoLOmwvc1GyqlIKOK1nN94nHPoltGRhWhw7Zx0-
kFm1NJn8LE9XShH59_i8J0PH5ZZyNfGy2xGdULU7sHNF6Gp2vPLgNZ__deLKx
GHZ7PcHALUzoOegEI-8E66jX2E4zyJKx-YxzZIItRzC5hlRirb6Y5Cl_p-ko3
YvkkysZIFNPccxRU7qve1WYPxqbb2Yw8kZqa2rMWI5ng8OtvzlV7elprCbuPh
cCdZ6XDP0_F8rkXds2vE4X-ncOIM8hAYHHi29NX0mcKiRaD0-D-ljQTP-cFPg
wCp6X-nZZd9OHBv-B3oWh2TbqmScqXMR4gp_A"},
{"header":
{"alg":"A128KW","kid":"7"},
"encrypted_key":
"6KB707dM9YTIgHtLvtgWQ8mKwboJW3of9locizkDTHzBC2IlrT1oOQ"}],
"iv":
"AxY8DCtDaGlsbGljb3RoZQ",
"ciphertext":
"KDlTtXchhZTGufMYmOYGS4HffxPSUrfmqCHXaI9wOGY",
"tag":
"Mz-VPPyU4RlcuYv1IwIvzw"
}
This example shows the steps in the AES_128_CBC_HMAC_SHA_256 authenticated encryption computation using the values from the example in Appendix A.3. As described where this algorithm is defined in Sections 5.2 and 5.2.3 of JWA, the AES_CBC_HMAC_SHA2 family of algorithms are implemented using Advanced Encryption Standard (AES) in Cipher Block Chaining (CBC) mode with PKCS #7 padding to perform the encryption and an HMAC SHA-2 function to perform the integrity calculation - in this case, HMAC SHA-256.
The 256 bit AES_128_CBC_HMAC_SHA_256 key K used in this example (using JSON array notation) 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]
Use the first 128 bits of this key as the HMAC SHA-256 key MAC_KEY, which is:
[4, 211, 31, 197, 84, 157, 252, 254, 11, 100, 157, 250, 63, 170, 106, 206]
Use the last 128 bits of this key as the AES CBC key ENC_KEY, which is:
[107, 124, 212, 45, 111, 107, 9, 219, 200, 177, 0, 240, 143, 156, 44, 207]
Note that the MAC key comes before the encryption key in the input key K; this is in the opposite order of the algorithm names in the identifiers "AES_128_CBC_HMAC_SHA_256" and A128CBC-HS256.
Encrypt the Plaintext with AES in Cipher Block Chaining (CBC) mode using PKCS #7 padding using the ENC_KEY above. The Plaintext in this example is:
[76, 105, 118, 101, 32, 108, 111, 110, 103, 32, 97, 110, 100, 32, 112, 114, 111, 115, 112, 101, 114, 46]
The encryption result is as follows, which is the Ciphertext output:
[40, 57, 83, 181, 119, 33, 133, 148, 198, 185, 243, 24, 152, 230, 6, 75, 129, 223, 127, 19, 210, 82, 183, 230, 168, 33, 215, 104, 143, 112, 56, 102]
The Additional Authenticated Data (AAD) in this example 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, 81, 48, 74, 68, 76, 85, 104, 84, 77, 106, 85, 50, 73, 110, 48]
This AAD is 51 bytes long, which is 408 bits long. The octet string AL, which is the number of bits in AAD expressed as a big endian 64 bit unsigned integer is:
[0, 0, 0, 0, 0, 0, 1, 152]
The Initialization Vector value used in this example is:
[3, 22, 60, 12, 43, 67, 104, 105, 108, 108, 105, 99, 111, 116, 104, 101]
Concatenate the AAD, the Initialization Vector, the Ciphertext, and the AL value. The result of this concatenation 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, 81, 48, 74, 68, 76, 85, 104, 84, 77, 106, 85, 50, 73, 110, 48, 3, 22, 60, 12, 43, 67, 104, 105, 108, 108, 105, 99, 111, 116, 104, 101, 40, 57, 83, 181, 119, 33, 133, 148, 198, 185, 243, 24, 152, 230, 6, 75, 129, 223, 127, 19, 210, 82, 183, 230, 168, 33, 215, 104, 143, 112, 56, 102, 0, 0, 0, 0, 0, 0, 1, 152]
Compute the HMAC SHA-256 of the concatenated value above. This result M is:
[83, 73, 191, 98, 104, 205, 211, 128, 201, 189, 199, 133, 32, 38, 194, 85, 9, 84, 229, 201, 219, 135, 44, 252, 145, 102, 179, 140, 105, 86, 229, 116]
Use the first half (128 bits) of the HMAC output M as the Authentication Tag output T. This truncated value is:
[83, 73, 191, 98, 104, 205, 211, 128, 201, 189, 199, 133, 32, 38, 194, 85]
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.REC-xmlenc-core1-20130411] and RFC 5652 [RFC5652] as possible, while utilizing simple, compact JSON-based data structures.
Special thanks are due to John Bradley, Eric Rescorla, and Nat Sakimura for the discussions that helped inform the content of this specification, to Eric Rescorla and Joe Hildebrand for allowing the reuse of text from [I-D.rescorla-jsms] in this document, and to Eric Rescorla for co-authoring many drafts of this specification.
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, Matt Miller, Tony Nadalin, Hideki Nara, Axel Nennker, Emmanuel Raviart, Eric Rescorla, Nat Sakimura, Jim Schaad, Hannes Tschofenig, and Sean Turner.
Jim Schaad and Karen O'Donoghue chaired the JOSE working group and Sean Turner, Stephen Farrell, and Kathleen Moriarty served as Security area directors during the creation of this specification.
[[ to be removed by the RFC Editor before publication as an RFC ]]
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