thumb|A miniature portrait of Marcabru beside his vida in a 13th-century chansonnier. Marcabru (; fl. 1130–1150) is one of the earliest troubadours whose poems are known. There is no certain informati
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 Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd1bae914d25cea508d2f4c15bf4f51a0652e903216706810d6e84eea7b29f24b. Chain 2 (Bitcoin): anchored in block 954065 (2026-06-17T08:10:43Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/4c3772bf-f30b-4588-b677-af303e80814e.json and https://artists.proofprofile.net/proofs/artist/4c3772bf-f30b-4588-b677-af303e80814e.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 Note: an OTS proof may carry multiple Bitcoin attestations; OTSBitcoinBlock is the earliest confirmed one — a later attestation inside the proof corroborates it and is not a mismatch
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4691f9dba6ec08b1c64d0a65b871ab5f5f9f1f2b31571b046c7bc38e52cd0d14. Chain 2 (Bitcoin): anchored in block 960218 (2026-07-30T06:57:05Z), 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/BER181334001.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x531ddc9b83fecb8ef9cf541905304a79f569fdd99cafdf94e21d58a29e59c2b1. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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/DEB338836804.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa249c0240ca38ec407b66c043c1b5fc71b1a0fdf779787eba9115591f9ed97bd. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/FRZ147704070.
Moyen Age: Musique instrumentale du moyen âge (Instrumental music of the Middle Ages)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2bf85e334875087a8b144e06ae56a89b70eeaf1f52508dd6755f868a155b3b79. Chain 2 (Bitcoin): anchored in block 957061 (2026-07-07T16:07:00Z), 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/CH1409807113.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xafbbda5b940ef6049d439ffc82a462dedaf1a8d6f25f636da88e9a2fc017ceb0. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/GBF077040702.
Magna Melodia - Medieval Music From The Time Of The Magna Carta
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7991c57a6d294dd63e40ae8e702e2f86ed69657be58bf708bf23692ba0513f4d. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/DELJ81590697.