Proof of Existence
Useful for designers, photographers, writers and developers who want a dated record of their work, or for anyone who wants to show a file has not changed since a given day. The file itself is never stored.
Log in to use this tool. New accounts get 10 free credits.
How to use Proof of Existence
- 1
Upload any file up to 10 MB. A verified email is required.
- 2
Click Process. We record the file fingerprint, name, size and the exact time, and you download a PDF certificate.
- 3
Keep the original file unchanged. Anyone can drop it on the verification page to see when it was registered.
Questions about this tool
Is my file uploaded and kept?
It is processed in memory to compute its fingerprint and then discarded. Only the fingerprint, file name, size and time are stored.
Does this prove I made the file?
No. It proves the exact file existed at the time it was registered. Combined with your other records it can support a claim, but it is not proof of authorship or a qualified electronic timestamp.
What if I edit the file later?
An edited file has a different fingerprint and will not match. Register the new version separately if you need a record of it too.