RFC 3161 TSP

IETF trusted-timestamping protocol; the building block of the -T level of AdES signatures.

Definition

A client sends the hash of some data to a Time-Stamping Authority (TSA), which returns a Time-Stamp Token (TST), a signed CMS structure binding that hash to a trusted time. This is exactly the token added by XAdES-T, CAdES-T and PAdES-T (the B-T level) to fix the signing date and underpin B-LTA archival.

Origin

Defined by the IETF in RFC 3161 (Internet X.509 PKI Time-Stamp Protocol, 2001), updated by RFC 5816. ETSI EN 319 422 profiles its use for eIDAS trust services.

Example in context

TimeStampReq request: { hashAlgorithm: SHA-256, hashedMessage: <digest> }. TimeStampResp response carrying a TSTInfo signed by the TSA with genTime = 2026-06-20T10:15:00Z.

Related terms

• AdES baseline levels — the TST realises the B-T level.
• CAdES — the TST is itself a CMS structure.