The Stamper Timestamping Service has been in operation since 1995 and has been significantly upgraded in 2025, with these changes.
It provides PGP timestamps and (more recently) RFC 3161 timestamps. PGP timestamps are available via email and HTTPS, whereas RFC 3161 timestamps are only via HTTPS.
It prevents timestamps being backdated by timestamping all its signatures for the previous day, that signature in turn being in the following day's timestamps. This is similar to blockchain, albeit that blockchain did not yet exist in 1995.
For the RFC 3161 timestamps, each "timestamp response" (TSR) is also timestamped with PGP, with the PGP signature going into set for daily signing. The PGP signature and the TSR have the same number.
Every timestamp issued is serial numbered, and all timestamps (but not the data which was timestamped) is a matter of public record not available from a Git repository.
The service is free to use subject to each user's acceptance of these Terms of use.
It provides the following services:-
Additionally:-