NORDIK, or the Nordic Association for Art Historians, is an association of art historians from universities and museums in the Nordic countries. The committee was founded in Helsinki in 1984 to promot
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 0xd4266f9468621a5738d47cfb7592630938c0c8deba39fcf1a56a07a322488348. Chain 2 (Bitcoin): anchored in block 953697 (2026-06-14T21:49:28Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/5dafe02a-81bf-467b-9ae7-c660bb62e30c.json and https://artists.proofprofile.net/proofs/artist/5dafe02a-81bf-467b-9ae7-c660bb62e30c.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 0x7f0489d795be1f3f9b50c806f4b10094e9df7053bb54adc3559023e14277f1a3. Chain 2 (Bitcoin): anchored in block 958594 (2026-07-18T18:05:01Z), 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/USHM81867481.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2fce272326862031de9033249c73767488982bfdc7f2313301f180c39fa24b02. Chain 2 (Bitcoin): anchored in block 958805 (2026-07-20T02:22:58Z), 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/USHM81867487.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe5ca85763363aec2220cfc8afaaee02f7b5db3756390b1696c7a07766b320478. Chain 2 (Bitcoin): anchored in block 958765 (2026-07-19T18:01:47Z), 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/USHM81867488.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4e59a666bb732a2efdb4a87b1e48a4e6be4b938bf362fa73809309a7a2e5cc62. Chain 2 (Bitcoin): anchored in block 958788 (2026-07-19T22:07:06Z), 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/USHM81867492.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4bfdc1931d137c022b9ae17aa847f9978934569706e2b78697c93e42bb85be24. Chain 2 (Bitcoin): anchored in block 958823 (2026-07-20T07:09:00Z), 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/USHM81867493.