Los Carpinteros is a Cuban artist collective founded in Havana in 1992 by Marco Antonio Castillo Valdes, Dagoberto Rodriguez Sanchez, and Alexandre Arrechea (who left the group in 2003). In 1994 they
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 0xadb0d3b3090ffd2a5b05e3b8b4b4944b3e7c2dec01773287fd58964e4d29c082. Chain 2 (Bitcoin): anchored in block 953633 (2026-06-14T12:47:11Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/353714db-3329-4245-8d87-4dfbb050f1a3.json and https://artists.proofprofile.net/proofs/artist/353714db-3329-4245-8d87-4dfbb050f1a3.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 0x461d417e6734aff8704d0fed30921e97ab06f1c4025f55dbf4c4bbac4a95b979. Chain 2 (Bitcoin): anchored in block 959100 (2026-07-22T05:29:55Z), 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/USHM91678628.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x73d36b34f02c72997d99fd30affabe42dc4e708f4aaed3b97c71224fc67f7d88. Chain 2 (Bitcoin): anchored in block 956545 (2026-07-03T19:59:51Z), 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/USHM91678631.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x009e480d2ae78c2084aed83d1bffe583157edc51938136487f3e37c60e258226. Chain 2 (Bitcoin): anchored in block 958779 (2026-07-19T21:08:39Z), 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/USHM91678632.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x941c2ddf50daefd19a86b8e6de13fe6424477007a8076c5dd8b34c6dbf99766a. Chain 2 (Bitcoin): anchored in block 956634 (2026-07-04T10:04:33Z), 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/USDY41975133.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd6e8038334192c0ced9ada88773d9eb5b00f6ef5b6560d944adddece21a39f30. Chain 2 (Bitcoin): anchored in block 956822 (2026-07-05T18:48:28Z), 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/USDY41975136.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x14bd266735b608ec4527be010002550cddea16151f12072a6b25b99dcec4bb64. Chain 2 (Bitcoin): anchored in block 956420 (2026-07-03T00:42:11Z), 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/USDY41975137.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd4bc44b291fe7090f032786aba0c43c7a47cc143834fe9626ef32c7d55b9de9b. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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/USDY41975142.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa697631ff639ccce1cd314c3b321b275c33c185b76d4558519566c47722432ae. Chain 2 (Bitcoin): anchored in block 959146 (2026-07-22T15:41:47Z), 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/USDY42138894.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5e26c217f509e80c9325beab0d5a4a727243b3fb33c009903db35acb678db5dc. Chain 2 (Bitcoin): anchored in block 956634 (2026-07-04T10:04:33Z), 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/USDY42138896.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5b2285da3a176574e3dd013a15aae1d5f18e4dcc107f184b10bbd8260e1286f3. 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/USDY42138897.