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x5t

IESG

Registry Context

Carries the SHA-1 thumbprint of the X.509 certificate associated with a JWK.

Technical Summary

The `x5t` JWK parameter contains the base64url-encoded SHA-1 digest of the DER encoding of an X.509 certificate. The certificate's key must match the public key represented by the JWK, and any other JWK members must be semantically consistent with related certificate fields.

When Used

When a JWK includes the SHA-1 thumbprint of an associated X.509 certificate.

Normative Requirements

Optional JWK members providing key usage, algorithm, or other information

MAY
1
  1. RFC 7517 - Section 4.8

    also be present..

    Condition: When the `x5t` member is used.

    optional JWK members providing key usage, algorithm, or other information MAY also be present

The contents of other JWK members

MUST
1
  1. RFC 7517 - Section 4.8

    be semantically consistent with related fields in the referenced certificate..

    Condition: If other JWK members are present with `x5t`.

    the contents of those members MUST be semantically consistent with the related fields in the referenced certificate.

The key in the certificate

MUST
1
  1. RFC 7517 - Section 4.8

    match the public key represented by other members of the JWK..

    Condition: When the `x5t` member is used.

    The key in the certificate MUST match the public key represented by other members of the JWK.

Use of the `x5t` member

OPTIONAL
1
  1. RFC 7517 - Section 4.8

    be optional..

    Use of this member is OPTIONAL.

Validation Guidance

error

Validate that `x5t` is a base64url-encoded SHA-1 digest of the DER encoding of the associated X.509 certificate.

error

When the associated certificate is available, verify that its key matches the public key represented by the JWK.

info

Do not require `x5t` for a JWK to be valid.

error

If other JWK members are present with `x5t`, verify that their contents are semantically consistent with related fields in the associated certificate.

Reference

Details

Entry Id
x5t
Parameter Name
x5t
Parameter Description
X.509 Certificate SHA-1 Thumbprint
Used With Kty Value
*
Parameter Information Class
Public
Change Controller
IESG
Reference
RFC7517 - Section 4.8