REVINFO

REVINFO stands for Revocation Information and refers to an optional metadata attribute used in certain public key infrastructure protocols to convey the revocation status of certificates involved in a digital timestamp or signature. It is commonly associated with time-stamp tokens and other CMS-based signatures, where a trusted authority may include revocation data to support later verification.

In typical use, REVINFO carries a set of revocation information entries. Each entry records data about a certificate’s revocation status as of a specific time, often tying the status to cryptographic identifiers such as hashes of the issuer and the certificate itself. The information may reference revocation mechanisms such as certificate revocation lists (CRLs) or OCSP responses, and it aims to reflect the certificate’s state at the moment of the timestamp or signing event.

Purpose and benefits include enhancing long-term verifiability. By providing a snapshot of revocation status at the time of the token’s creation, REVINFO helps verify that the certificates used were not revoked at that time, even if revocation events occur later. This supports non-repudiation and improves confidence in the time-stamped assertion when certificates later become untrusted.

Limitations and considerations involve practical trade-offs. REVINFO increases the size of the token, relies on the availability and accuracy of up-to-date revocation data, and is not uniformly supported across all implementations. Its usefulness depends on the reliability of the revocation sources referenced (CRLs or OCSP responses) and the policies of the issuing authority.

See also: Time-Stamp Protocol, CMS, PKI.