vDPO Proof

vDPO Proof records a digital fingerprint of any file on a public blockchain, so you can later show that exactly that file existed at that time. Anyone can verify a proof, for free.

What a proof shows

• The exact file, identified by its fingerprint (a SHA-256 hash).
• That it existed no later than the time it was recorded.
• Whether a copy is unchanged: even a one-character change gives a different fingerprint.

When to use it

For any record you may one day need to prove has not changed: confidential information shared under a non-disclosure agreement, each version of a privacy notice as it is published, an incident report and the notifications sent, or an approved assessment.

Creating a proof

1. Go to Create Proof.
2. Choose the file. Its fingerprint is made in your browser; the file never leaves your device.
3. Add a label and, if you like, private notes, then record the proof. Each proof uses one credit.

Your proofs are listed under My Proofs. Keep the original file: the proof is only useful alongside it.

Verifying a proof

Go to Verify Proof and choose the file, or open a proof’s link. vDPO fingerprints the file in your browser and checks it against the blockchain record. No account is needed.

Credits

Buy credits on the vDPO Proof page. Credits are valid for three years. If a proof cannot be recorded, its credit is returned automatically. See the Evidence Guide for how to use proofs as evidence, and the vDPO Proof Terms.