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Standards2025-03-05· 4 min

RFC 3161 Timestamps: Proving When Your Content Was Created

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Proving that a file existed at a specific point in time — and hasn't changed since — is a core requirement of legal, journalistic, and archival workflows. RFC 3161 is the internet standard that makes this possible with cryptographic certainty.

What an RFC 3161 timestamp contains

When AuthenSeal submits your file's SHA-256 hash to a trusted Timestamp Authority (TSA), the TSA returns a signed response containing:

  • The hash of your file — proving exactly which file was timestamped
  • The exact UTC time according to the TSA's authoritative clock
  • A digital signature from the TSA's certificate — which can be independently verified by anyone

Why this matters legally

RFC 3161 timestamps are recognised under EU eIDAS regulation as a qualified electronic timestamp, giving them legal weight equivalent to a notarised date in many jurisdictions. For journalists protecting sources, photographers asserting priority of capture, or companies archiving signed contracts — this is the standard that holds up in court.

AuthenSeal uses TSAs from the Adobe Approved Trust List (AATL), ensuring maximum cross-platform compatibility. The timestamp token is stored in your seal record and embedded in the PDF certificate — downloadable at any time.

rfc3161-timestamp

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