The point that may matter later.
Keep the file.
Keep the proof.
ProofStamp adds independent time evidence to an important file, so you can verify the exact record you kept later.
Opens They Told Me by ProofStamp. It also works with PDFs, photos and other files within the app’s limits.
The original stays on your device.
The proof is tied to the exact file you selected.
Illustrative example
A handover report is saved. Later, another copy appears.
Email, folders and backups already help people keep records. At handover, ProofStamp adds an independent time checkpoint for the exact PDF.
Months later, a second copy appears. The earlier ProofStamp gives you something concrete to compare against.
Example filenames, time and results are illustrative.
How it works
Add one checkpoint. Check it when it matters.
ProofStamp does not replace email, folders or backups. It adds independent evidence for the exact files you choose.
Choose
Select one or more files you want to preserve.
ProofStamp
Your browser hashes the files locally and gets an independently signed time for the proof.
Keep
Download one ProofStamp ZIP containing the originals and verification evidence.
Check later
Open Check ProofStamp and choose the saved ZIP. Verification runs on your device.
Technical details
ProofStamp uses SHA-256 and an RFC 3161 signed timestamp. The browser verifier checks the files in the saved package against the recorded hashes and verifies the saved timestamp evidence on your device. The current browser verifier does not perform OCSP or CRL revocation checks.
The payoff
Check the record you actually kept.
A successful check shows that the exact file bytes in the ProofStamp existed no later than the signed time.
It does not prove that the report is true, who created it, when the handover actually happened, or how a dispute should be decided.
Before the version becomes the question
Start with one important file.
Add the checkpoint while the record is still fresh.