Certificate of authenticity · Verification code 4LJ3BAYCE2 · Version 1
Cro Magnon 4.0 Cavepainting A.D. 2016 I
Tim Berresheim
| Inventory number | TB16/P 82/1 |
|---|---|
| Year | 2016 |
| Technique | Harz und Pigmente auf Papier |
| Dimensions | 140 × 110 cm |
| Edition | 1/3 |
| Issued | 13.11.2026, 08:06 |
Timestamp anchored in Bitcoin, block 975648.
Verification
- …Checksum of the certificate file
- …Artist’s signature
- …Timestamp in Bitcoin
- ·ImageDrop the image file here to compare it with the certificate.
Drop a file here: image, certificate (.json), signature (.sig) or timestamp (.ots). Nothing is uploaded; everything is computed in your browser.
Verification data
- SHA-256 of the certificate file
9632260e5ef386da3a9ddb79c01727f12514b5a71a216ee5ff3046aded5460ac- Signature (Ed25519, Base64)
DRZus/Yd0nP6y8aw/I2UewjrSJ5Zs4FrHqhv6rLTs4GAu6cn4j24GHH/3oSpb64BgFd57JWfTknHwELmJbRpBA==- Artist’s public key
0a347c3cdcf869a45213eb6eea4e65d4f60adb6d1fe7d9be59eace1f04584708- SHA-256 of the main image
5e3f1a72b3d4d0bd10a85a6f8baef41a2e53a36efc9d6660eb48d9a7b92157c8
How to verify this independently of this page: hash the JSON file with SHA-256; the value must match the checksum above. Verify the signature against that checksum with the public key (Ed25519). Check the .ots file together with the JSON file at opentimestamps.org: this proves since when the checksum has been in the Bitcoin blockchain. The proof depends neither on this address nor on the artist, only on certificate, key and blockchain.