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How does timestamping work?

Timestamping with ProofYouWereFirst is simple:

  1. Hash your file: We create a cryptographic fingerprint (SHA-256 hash) of your file in your browser. Your file never leaves your device.
  2. Anchor on Bitcoin: That hash is embedded in a Bitcoin transaction using OpenTimestamps, linking it to a specific block height.
  3. Generate proof: You receive a downloadable certificate (PDF + .ots file) that anyone can verify independently.

This process is free, private, and permanent. The Bitcoin blockchain acts as a decentralized notary that can't be tampered with.

Other Questions

Is my file private?

Yes. Your file never leaves your browser. Only the cryptographic fingerprint (hash) is sent for proof.

Is this legally recognized?

Bitcoin timestamps are accepted as admissible digital evidence in multiple jurisdictions. They prove a file existed at a specific time.

Can I verify someone else's proof?

Yes—anyone can independently verify a proof on-chain using our verification page or OpenTimestamps explorer.

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