Fingerprint Registry

Timestamped evidence · RFC 3161

Prove a fingerprint existed by a given moment.

Register the SHA-256 fingerprint of any file. The file is hashed in your browser and never leaves your device. Each entry is chained to the one before it, so tampering shows.

Free for everyone. No accounts, no limits, no payments.

Register a fileVerify a file

1 · Fingerprint

Web Crypto computes a SHA-256 hash locally. 64 hex characters that change completely if one byte changes.

2 · Chain

Each ledger entry stores the previous entry's hash. Altering or removing any record breaks the chain visibly.

3 · Verify

Drop the same file later. If its fingerprint is on the ledger, you see exactly when it was registered.

Free for everyone

No accounts, no limits, no payments. Register and verify as many files as you like.

What it proves — and what it doesn't

Proves

  • This exact SHA-256 fingerprint was registered no later than the stated time.
  • Any file producing this fingerprint existed, byte-for-byte, by that time.
  • The record sits in a hash chain: altering or removing it breaks the chain visibly.

Does not prove

  • Who created or authored the document.
  • Whether the contents of the document are true.
  • When the document was originally written or created.

FAQ

Is my file uploaded?

No. Only the 64-character fingerprint is stored. The file cannot be rebuilt from it.

Is this a real RFC 3161 timestamp?

Not by itself. Times here come from your device clock (or the server clock if you run the backend). A true RFC 3161 timestamp needs a Timestamp Authority (TSA) such as FreeTSA to sign the hash. You can send the fingerprint to a TSA with openssl ts.

Does the Safety Check replace antivirus?

No. This flags common warning signs; it is not a full antivirus. A clean result doesn't guarantee a file is safe. It looks for disguised programs, macros, risky PDF actions, suspicious archives and scam/malware patterns in text, all inside your browser. Use the VirusTotal button for a second opinion.

Is the ledger public?

In static mode the ledger lives in this browser's localStorage — export it as JSON to share or back it up. A shared public ledger needs the included Python backend (or another server).

What does "chain intact" mean?

Every entry's hash is recomputed from its contents plus the previous entry's hash. If anything was edited, deleted or reordered, the check fails and shows where.

Register

Choose a file to fingerprint

Verify

Check a file against the ledger

Public Ledger

Hash-chained entries

#RegisteredFingerprintLabelEntry hash

Safety Check

Check a file or text for warning signs

This flags common warning signs; it is not a full antivirus. A clean result doesn't guarantee a file is safe.