Internet DRAFT - draft-jones-json-web-encryption-json-serialization
draft-jones-json-web-encryption-json-serialization
JOSE Working Group M. Jones
Internet-Draft Microsoft
Intended status: Standards Track July 6, 2012
Expires: January 7, 2013
JSON Web Encryption JSON Serialization (JWE-JS)
draft-jones-json-web-encryption-json-serialization-02
Abstract
The JSON Web Encryption JSON Serialization (JWE-JS) is a means of
representing encrypted content using JavaScript Object Notation
(JSON) data structures. This specification describes a means of
representing secured content as a JSON data object (as opposed to the
JWE specification, which uses a compact serialization with a URL-safe
representation). It enables the same content to be encrypted to
multiple parties (unlike JWE). Cryptographic algorithms and
identifiers used with this specification are described in the
separate JSON Web Algorithms (JWA) specification. The JSON
Serialization for related digital signature and HMAC functionality is
described in the separate JSON Web Signature JSON Serialization
(JWS-JS) specification.
Status of this Memo
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This Internet-Draft will expire on January 7, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Notational Conventions . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. JSON Serialization . . . . . . . . . . . . . . . . . . . . . . 3
4. Example JWE-JS . . . . . . . . . . . . . . . . . . . . . . . . 4
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 5
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
7. Open Issues . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 6
8.1. Normative References . . . . . . . . . . . . . . . . . . . 6
8.2. Informative References . . . . . . . . . . . . . . . . . . 6
Appendix A. Acknowledgements . . . . . . . . . . . . . . . . . . . 7
Appendix B. Document History . . . . . . . . . . . . . . . . . . . 7
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 7
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1. Introduction
The JSON Web Encryption JSON Serialization (JWE-JS) is a format for
representing encrypted content as a JavaScript Object Notation (JSON)
[RFC4627] object. It enables the same content to be encrypted to
multiple parties (unlike JWE [JWE].) The encryption mechanisms are
independent of the type of content being encrypted. Cryptographic
algorithms and identifiers used with this specification are described
in the separate JSON Web Algorithms (JWA) [JWA] specification. The
JSON Serialization for related digital signature and HMAC
functionality is described in the separate JSON Web Signature JSON
Serialization (JWS-JS) [JWS-JS] 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
This specification uses the same terminology as the JSON Web
Encryption (JWE) [JWE] specification.
3. JSON Serialization
The JSON Serialization represents encrypted content as a JSON object
with members for each of four constituent parts: a "headers" member
whose value is a non-empty array of Encoded JWE Header values, an
"encrypted_keys" member whose value is a non-empty array of Encoded
JWE Encrypted Key values, a "ciphertext" member whose value is an
Encoded JWE Ciphertext value, and an "integrity_values" member whose
value is a non-empty array of Encoded JWE Integrity Value values.
The number of elements in each of the arrays MUST be the same.
Unlike the compact serialization used by JWEs, content using the JSON
Serialization MAY be encrypted to more than one recipient. Each
recipient requires:
o a JWE Header value specifying the cryptographic parameters used to
encrypt the JWE Encrypted Key to that recipient and the parameters
used to encrypt the plaintext to produce the JWE Ciphertext; these
values are represented as Encoded JWE Header values that are
elements of the non-empty array contained in the "headers" member.
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o a JWE Encrypted Key value; these values are represented as Encoded
JWE Encrypted Key values that are corresponding elements of the
non-empty array contained in the "encrypted_keys" member.
o a JWE Integrity Value that ensures the integrity of the Ciphertext
and the parameters used to create it; these values are represented
as Encoded JWE Integrity Value values that are corresponding
elements of the non-empty array contained in the
"integrity_values" member.
Therefore, the syntax is:
{"headers":["<header 1 contents>",...,"<header N contents>"],
"encrypted_keys":["<key 1 contents>",...,"<key N contents>"],
"ciphertext":"<ciphertext contents>",
"integrity_values":["<value 1 contents>",...,"<value N contents>"]
}
The contents of the Encoded JWE Header, Encoded JWE Encrypted Key,
Encoded JWE Ciphertext, and Encoded JWE Integrity Value values are
exactly as specified in JSON Web Encryption (JWE) [JWE]. They are
interpreted and validated in the same manner, with each corresponding
"headers", "encrypted_keys", and "integrity_values" value being
created or validated together. The arrays MUST have the same number
of elements.
The i'th JWE Encrypted Key value and the i'th JWE Integrity Value are
computed using the parameters of i'th JWE Header value in the same
manner described in the JWE specification. This has the desirable
result that each Encoded JWE Encrypted Key value in the
"encrypted_keys" array and each Encoded JWE Integrity Value in the
"integrity_values" array are identical to the values that would have
been computed for the same header and payload in a JWE, as is the JWE
Ciphertext value.
All recipients use the same JWE Ciphertext value, resulting in
potentially significant space savings if the message is large.
Therefore, all header parameters that specify the treatment of the
JWE Ciphertext value MUST be the same for all recipients. In
particular, this means that the "enc" (encryption method) header
parameter value in the JWE Header for each recipient MUST be the
same, as MUST be the "iv" (initialization vector) value (when
required for the algorithm).
4. Example JWE-JS
This section contains an example using the JWE JSON Serialization.
This example demonstrates the capability for encrypting the same
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plaintext to multiple recipients.
Two recipients are present in this example: the first using the
RSAES-PKCS1-V1_5 algorithm to encrypt the Content Master Key (CMK)
and the second using the AES Key Wrap algorithm to encrypt the CMK.
The Plaintext is encrypted using the AES CBC algorithm to produce the
JWE Ciphertext. The two Decoded JWE Header Segments used are:
{"alg":"RSA1_5",
"x5t":"7noOPq-hJ1_hCnvWh6IeYI2w9Q0",
"enc":"A128CBC",
"iv":"__79_Pv6-fj39vX08_Lx8A",
"int":"HS256"}
and:
{"alg":"A128KW",
"enc":"A128CBC",
"iv":"__79_Pv6-fj39vX08_Lx8A",
"int":"HS256"}
The complete JSON Web Encryption JSON Serialization (JWE-JS) for
these values is as follows (with line breaks for display purposes
only):
{"headers":[
"eyJhbGciOiJSU0ExXzUiLA0KICJlbmMiOiJBMjU2Q0JDIiwNCiAiaW50IjoiS
FMyNTYiLA0KICJpdiI6Ik16LW1XXzRKSGZnIiwNCiAieDV0IjoiN25vT1BxLWhKM
V9oQ252V2g2SWVZSTJ3OVEwIn0",
"eyJhbGciOiJFQ0RILUVTIiwNCiAiZW5jIjoiQTI1NkNCQyIsDQogImVwayI6e
w0KICAiYWxnIjoiRUMiLA0KICAiY3J2IjoiUC0yNTYiLA0KICAieCI6IjIzNVJUN
2lLVEkzS1d2UzRfbUl3VWhYNk9DX1gySS1ic09wUzV3N01HQTQiLA0KICAieSI6I
lpTdjBkdHZYczRvMlhzSVZoRnpnaU1UU2c5dVNzeXRhT3ZDLVhSdGZvSU0ifSwNC
iAiamt1IjoiaHR0cHM6Ly9leGFtcGxlLmNvbS9wdWJsaWNfa2V5Lmp3ayJ9"],
"encrypted_keys":[
"TBD_encrypted_key_1_value_TBD",
"TBD_encrypted_key_2_value_TBD"],
"ciphertext":"TBD_ciphertext_value_TBD",
"integrity_values":[
"TBD_integrity_1_value_TBD",
"TBD_integrity_2_value_TBD"]
}
TBD: Finish this example.
5. IANA Considerations
This specification makes no requests of IANA.
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6. Security Considerations
The security considerations for this specification are the same as
those for the JSON Web Encryption (JWE) [JWE] specification.
7. 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 Complete the example.
o Track changes that occur in the JWE spec.
8. References
8.1. Normative References
[JWA] Jones, M., "JSON Web Algorithms (JWA)", July 2012.
[JWE] Jones, M., Rescorla, E., and J. Hildebrand, "JSON Web
Encryption (JWE)", July 2012.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC4627] Crockford, D., "The application/json Media Type for
JavaScript Object Notation (JSON)", RFC 4627, July 2006.
8.2. 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.
[JWS-JS] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature JSON Serialization (JWS-JS)", July 2012.
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Appendix A. Acknowledgements
JSON serializations for encrypted content were previously explored by
JSON Simple Encryption [JSE] and JavaScript Message Security Format
[I-D.rescorla-jsms].
Appendix B. Document History
[[ to be removed by the RFC editor before publication as an RFC ]]
-02
o Updated examples to track updated algorithm properties in the JWA
spec.
o Tracked editorial changes made to the JWE spec.
-01
o Tracked changes between JOSE JWE draft -00 and -01, which added an
integrity check for non-AEAD algorithms.
-00
o Created the initial version incorporating JOSE working group input
and drawing from the JSON Serialization previously proposed in
draft-jones-json-web-token-01.
Author's Address
Michael B. Jones
Microsoft
Email: mbj@microsoft.com
URI: http://self-issued.info/
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