Internet DRAFT - draft-santesson-svt-jws
draft-santesson-svt-jws
Network Working Group S. Santesson
Internet-Draft IDsec Solutions
Intended status: Informational R. Housley
Expires: 22 September 2022 Vigil Security
21 March 2022
JWS Signature Validation Token
draft-santesson-svt-jws-01
Abstract
This document defines a JSON Web Signature (JWS) profile for the
Signature Validation Token defined in [SVT].
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. SVT in JWS . . . . . . . . . . . . . . . . . . . . . . . . . 3
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3.1. "svt" Header Parameter . . . . . . . . . . . . . . . . . 3
3.2. Multiple SVT in a signature . . . . . . . . . . . . . . . 3
4. SVT Claims . . . . . . . . . . . . . . . . . . . . . . . . . 3
4.1. Profile Identifer . . . . . . . . . . . . . . . . . . . . 3
4.2. Signature Reference Data . . . . . . . . . . . . . . . . 4
4.3. Signed Data Reference Data . . . . . . . . . . . . . . . 4
4.4. Signer Certificate References . . . . . . . . . . . . . . 4
5. SVT JOSE Header . . . . . . . . . . . . . . . . . . . . . . . 5
5.1. SVT Signing Key Reference . . . . . . . . . . . . . . . . 5
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6.1. Header Parameter Names Registration . . . . . . . . . . . 5
6.1.1. Registry Contents . . . . . . . . . . . . . . . . . . 5
7. Security Considerations . . . . . . . . . . . . . . . . . . . 5
8. Normative References . . . . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
The "Signature Validation Token" specification [SVT] defines the
basic token to support signature validation in a way that can
significantly extend the lifetime of a signature.
This specification defines a profile for implementing SVT with a JWS
signed payload according to [RFC7515], and defines the following
aspects of SVT usage:
* How to include reference data related to JWS signatures in an SVT.
* How to add an SVT token to JWS signatures.
A JWS may have one or more signatures depending on its serialization
format, signing the same payload data. A JWS either contains the
data to be signed (enveloping) or may sign any externally associated
payload data (detached).
To provide a generic solution for JWS, an SVT is added to each
present signature as a JWS Unprotected Header. If a JWS includes
multiple signatures, then each signature includes its own SVT.
2. Definitions
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
BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
The definitions in [SVT] and [RFC7515] apply also to this document.
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3. SVT in JWS
An SVT token MAY be added to any signature of a JWS to support
validation of that signature. If more than one signature is present
then each present SVT MUST provide information exclusively related to
one associated signature and MUST NOT include information about any
other signature in the JWS.
Each SVT is stored in its associated signature's "svt" header as
defined in Section 3.1.
3.1. "svt" Header Parameter
The "svt" (Signature Validation Token) Header Parameter is used to
contain an array of SVT tokens to support validation of the
associated signature. Each SVT token in the array has the format of
a JWT as defined in [RFC7519] and is stored using its natural string
representation without further wrapping or encoding.
The "svt" Header Parameter, when used, MUST be included as a JWS
Unprotected Header.
Note: JWS Unprotected Header is not supported with JWS Compact
Serialization. A consequence of adding an SVT token to a JWS is
therefore that JWS JSON Serialization MUST be used, either in the
form of general JWS JSON Serialization (for one or more signatures)
or in the form of flattened JWS JSON Serialization (optionally used
when only one signature is present in the JWS).
3.2. Multiple SVT in a signature
If a new SVT is stored in a signature which already contains a
previously issued SVT, implementations can choose to either replace
the existing SVT or to store the new SVT in addition to the existing
SVT.
If a JWS signature already contains an array of SVTs and a new SVT is
to be added, then the new SVT MUST be added to the array of SVT
tokens in the existing "svt" Header Parameter.
4. SVT Claims
4.1. Profile Identifer
When this profile is used the SigValidation object MUST contain a
"profile" claim with the value "JWS".
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4.2. Signature Reference Data
The SVT Signature object MUST contain a "sig_ref" claim (SigReference
object) with the following elements:
* "sig_hash" -- The hash over the associated signature value (the
bytes of the base64url-decoded signature parameter).
* "sb_hash" -- The hash over all bytes signed by the associated
signature (the JWS Signing Input according to [RFC7515]).
4.3. Signed Data Reference Data
The SVT Signature object MUST contain one instance of the "sig_data"
claim (SignedData object) with the following elements:
* "ref" -- This parameter MUST hold one of the following thee
possible values.
1. The explicit string value "payload" if the signed JWS Payload
is embedded in a "payload" member of the JWS.
2. The explicit string value "detached" if the JWS signs detached
payload data without explicit reference.
3. A URI that can be used to identify or fetch the detached
signed data. The means to determine the URI for the detached
signed data is outside the scope of this specification.
* "hash" -- The hash over the JWS Payload data bytes (not its
base64url-encoded string representation).
4.4. Signer Certificate References
The SVT Signature object MUST contain a "signer_cert_ref" claim
(CertReference object). The "type" parameter of the
"signer_cert_ref" claim MUST be either "chain" or "chain_hash".
* The "chain" type MUST be used when signature validation was
performed using one or more certificates where some or all of the
certificates in the chain are not present in the target signature.
* The "chain_hash" type MUST be used when signature validation was
performed using one or more certificates where all of the
certificates are present in the target signature JOSE header using
the "x5c" Header Parameter.
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5. SVT JOSE Header
5.1. SVT Signing Key Reference
The SVT JOSE header must contain one of the following header
parameters in accordance with [RFC7515], for storing a reference to
the public key used to verify the signature on the SVT:
* "x5c" -- Holds an X.509 certificate [RFC5280] or a chain of
certificates. The certificate holding the public key that
verifies the signature on the SVT MUST be the first certificate in
the chain.
* "kid" -- A key identifier holding the Base64 encoded hash value of
the certificate that can verify the signature on the SVT. The
hash algorithm MUST be the same hash algorithm used when signing
the SVT as specified by the alg header parameter.
6. IANA Considerations
6.1. Header Parameter Names Registration
This section registers the "svt" Header Parameter in the IANA "JSON
Web Signature and Encryption Header Parameters" registry established
by [RFC7515].
6.1.1. Registry Contents
* Header Parameter Name: "svt"
* Header Parameter Description: Signature Validation Token
* Header Parameter Usage Location(s): JWS
* Change Controller: IESG
* Specification Document(s): Section 3.1 of {this document}
NOTE to RFC editor: Please replace {this document} with its assigned
RFC number.
7. Security Considerations
The security considerations of [SVT] applies also to this document.
8. Normative References
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[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[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, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>.
[RFC7515] Jones, M., Bradley, J., and N. Sakimura, "JSON Web
Signature (JWS)", RFC 7515, DOI 10.17487/RFC7515, May
2015, <https://www.rfc-editor.org/info/rfc7515>.
[RFC7519] Jones, M., Bradley, J., and N. Sakimura, "JSON Web Token
(JWT)", RFC 7519, DOI 10.17487/RFC7519, May 2015,
<https://www.rfc-editor.org/info/rfc7519>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
[SVT] Santesson, S. and R. Housley, "Signature Validation
Token", IETF draft-santesson-svt-02, September 2021.
Authors' Addresses
Stefan Santesson
IDsec Solutions AB
Forskningsbyn Ideon
SE-223 70 Lund
Sweden
Email: sts@aaa-sec.com
Russ Housley
Vigil Security, LLC
516 Dranesville Road
Herndon, VA, 20170
United States of America
Email: housley@vigilsec.com
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