Timestamp Camera with a Time Anyone Can Verify

It proves the time: our server signed the photo’s fingerprint at the moment shown, and an original file has not been changed since by a single byte. The place is what the device reported — GPS can be faked, so the stamp says «as the device reported» and shows the accuracy. The stamp does not prove when the scene itself happened: a photo of an old printout gets today’s time.

The big time on the stamp is our server’s time in your phone’s time zone. The phone’s own clock is printed in the report next to it with the difference («the phone clock is 3 min fast»), so a wrong clock on the phone does not change the stamp and does not leave anyone guessing which time is which.

A gallery photo was taken before it reached the page, and nobody can confirm when from the file alone: the date inside the file can be edited. So the stamp confirms what is certain — the photo existed by the moment it was added — and the date from the file goes into the report as the file’s own word.

Yes, partly. A messenger re-compresses the photo, so the byte-for-byte check of the file is no longer possible. The page reads the QR from the picture and compares the scene with the signed fingerprint: «matches», «similar but changed» or «does not match». For the exact check, ask for the original file or the PDF report.

The photo is saved on the device with the phone’s time and waits. When the network returns, it gets its stamp automatically; the stamp then says «not later than» the moment of confirmation and keeps the phone’s time of the shot beside it, marked as unverified.

Yes. The signature is ECDSA P-256 with a published public key, and the PDF carries the independent time-stamping token (timestamp.tsr) together with the exact bytes it signed and a short instruction for OpenSSL. Neither check needs our server.