What is a trusted timestamp?
A trusted timestamp binds a cryptographic hash to a specific point in time, issued by a time-stamping authority (TSA). It answers: “did this exact digital fingerprint already exist at time T?” — without revealing the underlying content.
RFC 3161
The Internet standard RFC 3161 defines the Time-Stamp Protocol. A TSA signs a time-stamp token that includes the hash you care about. Verifiers can validate the token chain and trust anchor without trusting ExistBefore’s web UI alone.
eIDAS and qualified timestamps
Under EU regulation 910/2014 (eIDAS), a qualified electronic timestamp has defined legal effects in member states. ExistBefore’s T1 layer adds this type of reinforcement through CertiSigma’s Merkle batching and TSA integration — asynchronous, typically within about an hour of T0.
How ExistBefore uses T1 and T2
- T1 — Merkle tree batch + qualified timestamp path (eIDAS-relevant).
- T2 — OpenTimestamps anchoring to the Bitcoin blockchain for long-term, publicly verifiable persistence.
T1 and T2 strengthen the same underlying hash; they do not replace independent verification of the hash or the T0 signature.
Related reading
How ExistBefore works · Technical overview · Proof of existence vs copyright
The CertiSigma API provides programmatic access to the same T0/T1/T2 pipeline. API documentation →