Frank Horvat (28 April 1928 – 21 October 2020) was an Italian photographer who lived and worked in France. He is best known for his fashion photography, published between the mid 1950s and the late 19
1. Compute SHA-256 of OTSCanonicalRecord value → must equal OTSHash 2. Open OTSProofURL → extract Bitcoin block number → must equal OTSBitcoinBlock 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Read CopyrightID inside OTSCanonicalRecord → must equal the CopyrightID above 5. GET OTSVerificationAPI → pre-computed 6-check result from server 6. If all match: this entity was registered on CopyrightChains at OTSTimestamp, independently verifiable on Bitcoin
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x07db0d40ac40856551efb5dc09546d9d76c596433b8ad01104ae091d86d19d44. Chain 2 (Bitcoin): anchored in block 954346 (2026-06-19T03:51:26Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/99bb70e4-9ad9-4d77-a8d8-7ccde6d6a1f3.json and https://artists.proofprofile.net/proofs/artist/99bb70e4-9ad9-4d77-a8d8-7ccde6d6a1f3.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
1. Confirm isrcCode identifies the recording in the pre-2022 source corpus and cc-db-prod record 2. GET OTSVerificationAPI → server-side canonical-record, hash, and attestation checks must pass 3. GET OTSBitcoinBlockVerifyURL → returns the Bitcoin block hash at height OTSBitcoinBlock; GET https://blockstream.info/api/block/{that hash} → its timestamp must match OTSTimestamp 4. Confirm CopyrightID is the CopyrightChains transaction hash 5. If all match: the cc-db-prod record is independently anchored on Bitcoin at OTSTimestamp
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x05105825a89c40a90e57a4b56f42a4b3c5e22ba45de043abf901980bc06b28f4. Chain 2 (Bitcoin): anchored in block 958771 (2026-07-19T22:19:08Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/CACS32100003.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfc1e0add9a496a8026087442e170207261df19f1a068d78d2a969c3e8bb30c62. Chain 2 (Bitcoin): anchored in block 958714 (2026-07-19T09:51:44Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/CACS32100017.
An Auditory Survey of the Last Days of the Holocene
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x12e0833283dde3340dfd4b964df7b657010f03c110772da8c563cc585b6c2921. Chain 2 (Bitcoin): anchored in block 956826 (2026-07-05T19:27:56Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USPMZ2518906.