Stamp a Document on Bitcoin

Free, private, zero-knowledge. Drop a file and get a Bitcoin-anchored proof of existence in under 60 seconds.

Three steps

1. Upload — your file is hashed locally (SHA-256); it never leaves your device.
2. Anchor — the fingerprint is submitted to OpenTimestamps calendars and embedded in the next Bitcoin block (~60 min).
3. Certify — download your .ots proof + PDF certificate. Independently verifiable forever.

Start stamping — free