The viola ( , () ) is a string instrument of the violin family, and is usually bowed when played. The viola is slightly larger than the violin and has a lower sound. Since the 18th century, it has bee
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 0xeb6bf97a34890bfda62696770965104e2df23b9d9c621bf14f05b6b28a7add39. Chain 2 (Bitcoin): anchored in block 954342 (2026-06-19T03:22:39Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/81b0127f-3233-4ae2-8f09-f0f3019269dc.json and https://artists.proofprofile.net/proofs/artist/81b0127f-3233-4ae2-8f09-f0f3019269dc.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 0x5d5a3a0da93e3f8a05a67cb899bc64c8499c569c31d1941a98b43a3cee3d46c7. Chain 2 (Bitcoin): anchored in block 958839 (2026-07-20T07:01:59Z), 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/TCAJB2482836.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x14c7eddde40e71b278c12e8c9e4d1618fcfee2c77e49c929921d2b7c6718c24f. 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/TCAJF2541092.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbdb2a4cc67377943e7f394f4c29ccbc5a4c13a438e0abb89b648ecf602412a44. Chain 2 (Bitcoin): anchored in block 959128 (2026-07-22T12:33:25Z), 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/FRX202554153.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9f656c668c73e35205e9e460a5280f425f7891515e63e39de5747968bcedb724. Chain 2 (Bitcoin): anchored in block 958825 (2026-07-20T04:55:29Z), 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/FRX202554154.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x77cb2fe25e8d8d2fe526eefa60b066f83a057c4d16d09c515f82e0c3391e8a98. Chain 2 (Bitcoin): anchored in block 958770 (2026-07-19T19:26:13Z), 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/FRX202554155.