Free forever · Runs in your browser
Sign & verify text provenance
Embed an invisible watermark and derive durable fingerprints, then prove authorship — even after the hidden characters are stripped. Signing is free. Verification is free. Your text never leaves this page.
A fresh Ed25519 key is generated in your browser each time you sign. Longer text (roughly 50+ words) carries the watermark; short text still gets fingerprints.