Drop in text or a file. We take a private fingerprint of it on your own machine and write that fingerprint into a public, tamper-evident record. Your file never leaves your device.
Nothing is uploaded. The fingerprint is computed in your browser.
Drop a file here or click to choose — or paste text below.
Nothing is uploaded — only the fingerprint leaves your browser.
Fingerprint is taken with your browser's built-in cryptography (Web Crypto). The original bytes stay on your device.
Sealed
Your document is sealed.
Here is what is actually proven. Each rung below is something a verifier's own browser can re-check — without trusting us.
Shareable proof link:
Anyone with this link can re-walk the record and confirm the fingerprint is in it. They never see your file.