thumb|upright=1.35|French F70 type frigates (here, ) are fitted with variable depth sonar (VDS) type DUBV43 or DUBV43C towed sonars. thumb|upright=1.35|A sonar image of the Soviet Navy minesweeper T-2
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 0x7ea62b19be8140c2dfb694c208af9a5bb96fd2ffc5d039bb596c9e462463e953. Chain 2 (Bitcoin): anchored in block 953407 (2026-06-12T19:24:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1cda2393-2b06-4f32-a752-774df8bcf576.json and https://artists.proofprofile.net/proofs/artist/1cda2393-2b06-4f32-a752-774df8bcf576.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 0x0b5c9a3f1cd18b27768d521bd1474b7e29d81ddd52c5f6e92d12f621b9020027. Chain 2 (Bitcoin): anchored in block 959001 (2026-07-21T11:41:42Z), 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/PLI861600126.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf8ae26c7c7fb676a2481bc4b05b6d0447292f3c3bea6f5892c92ddd12043de2b. Chain 2 (Bitcoin): anchored in block 959002 (2026-07-21T11:47:29Z), 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/PLI861800006.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7eda8fd4929a82d1ba8aa10d7aac3ab7c4acdb22887af7d64d03d6f1e271de56. Chain 2 (Bitcoin): anchored in block 956745 (2026-07-05T05:33:35Z), 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/PLI861700125.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfc1d37454a024bd8a65fed995613cb369769dcd16237ace4b9ca4fa4f183f6ea. Chain 2 (Bitcoin): anchored in block 959002 (2026-07-21T11:47:29Z), 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/PLI861800008.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x485c83a349b939a3f2d1c9ddf55d00508f2171389d434f14d52002b24e3743bb. Chain 2 (Bitcoin): anchored in block 958461 (2026-07-17T23:18:11Z), 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/PLB172001108.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe76ca423f9c630829b1fcbfe53978b6a2d67e2f79665e79a576925df90a7be79. Chain 2 (Bitcoin): anchored in block 956375 (2026-07-02T16:51:38Z), 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/PLB172200025.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb1a4d4f19919b30f1df73658f3a2ec9c073c67a560633611f5ad5b2e6a6c0c25. 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/PLA681802236.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x77b97c7d1a045fb37bf5b3069b08b347b97e78700345be7c4290ed4f349e06f7. 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/PLA681602050.