Co-sign a sealed document

Someone asked you to add your signature to a document stamp. You can sign only if you hold the identical file: this page fingerprints it on your device and compares it with the sealed one. The file is never uploaded.

Opening the co-sign link…

This link cannot be used

Your signature will be public. Your wallet address is added to the public record of this stamp. A co-signature must land the same UTC day as the stamp (), so the certificate is one record; after that the stamp stays sealed without it.

The sealed document

This is the record you were asked to co-sign.

1

Pick your copy of the file

Pick the file you were sent. It is fingerprinted here and compared with the sealed fingerprint. Only an identical file can be signed.

Fingerprinting on this device…
2

Sign

The fingerprint of your file is the sealed one. Connect your wallet and sign. You will see the exact fingerprint before your wallet opens. Your address must differ from the owner's.