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 0x73a28cd8263819cdf2ee65a6411f4d2334f4b755bcfee09bf9134993998072a0. Chain 2 (Bitcoin): anchored in block 953592 (2026-06-14T05:36:59Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/047ea928-a82e-49d1-8f80-23c0459b109a.json and https://artists.proofprofile.net/proofs/artist/047ea928-a82e-49d1-8f80-23c0459b109a.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 0x0e3d6d9dd3d7ee8edc5425359aa469ab6b058e6fdc5c4d14355d5e9530b771d8. Chain 2 (Bitcoin): anchored in block 958506 (2026-07-18T06:14:51Z), 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/FR10S1659363.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd29fcbd22e02c936eec933ea2f1cd3094664cdaee087ed5f09545753c70715f2. Chain 2 (Bitcoin): anchored in block 958690 (2026-07-19T07:14:39Z), 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/FR10S1671942.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x36c8600eabe0218f3aae902b4773bfa7d3c43bfbd072c5d755121c98e5b74055. Chain 2 (Bitcoin): anchored in block 958340 (2026-07-17T00:53:26Z), 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/FR10S1671948.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe319da390aeb1b8ae844f9091ce091afe652c2049dc0662602f22c1ac6346f8f. 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/FR10S1671833.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x57ed3617386ba2d7b7003a35ac735e75c9f21465070bacfe86f7369f46a26fd5. Chain 2 (Bitcoin): anchored in block 958543 (2026-07-18T11:58:44Z), 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/FR10S1671835.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x54b04bbe4ffc9ca415aa537bcd109cace881dddb204d6af306fca46fbcf23408. Chain 2 (Bitcoin): anchored in block 959009 (2026-07-21T13:14:47Z), 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/FR10S1657585.