What is timestamped proof of prior existence?

Timestamped proof of prior existence demonstrates that a file existed, in a specific state, at a specific date. Ipocamp computes your file's cryptographic fingerprint, has it timestamped by an independent time authority, then records it in a tamper-proof registry.

The resulting certificate links three elements: the file's fingerprint, the timestamp date, and your identity as the depositor. It's this combination that constitutes the proof.

In practical terms, the fingerprint is a 32-byte string computed from the file's content (a SHA-256 digest). It's unique to that file and can never be used to reconstruct its content.

To go further into the technical mechanics, see the Security page.