Contra may refer to: Places Contra, Virginia Contra Costa Canal, an aqueduct in the U.S. state of California Contra Costa County, California Tenero-Contra, a municipality in the district of Loc
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 0x2ebbe6aa09a0047c980b64a2dfb2ee3c0027f9ad810fa602d2f39de60210158c. 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/409f627b-1fe9-4289-a080-67ab63570665.json and https://artists.proofprofile.net/proofs/artist/409f627b-1fe9-4289-a080-67ab63570665.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 0xed9f5a79ae41a3c254ee50c2a7320120fcfe27517cec41e044a76c0f50ece27e. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/QM6N21854921.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x50035bd6db851e2b575b2698537d2da1a0ded5d131c1964dcb0fc81bf6a93cbc. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/TCADU1843430.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x14cba392c904274e45db13497e004d4712496532e56508b1fc3fbb21b954a6f9. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/QM6N21856296.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbb41c6583c24897124891582711ee98179cf4439cfd1b775428e258c5f68405d. 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/QM6N21856300.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcf4ff59b035a4fa4f1369d8b08733afab5bc36a0535d518a80c705212bbac03a. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/QM6N21856301.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc3db0336d48c9a5e62addd32d0188095133cd5fc357663192d74695f05706d40. 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/QM6N21856309.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc67a76ef5a3f8b97b5dd02bc4ef09616bc1923921581bea1f496e6ccd7da1286. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/QM6N21856319.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x86a01d0c419c742fcc4ef50f2be934b9c0d6c2b8274073ce7128c6c860194106. Chain 2 (Bitcoin): anchored in block 958180 (2026-07-15T20:12:00Z), 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/QM6N22355901.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7bad51817b4815c11644ee78dae73e70d29a4364eb26a603b9b0a9541cd8aa45. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/EEHU32000326.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x84f33697f2fd207de916c7e9b0fb0e51c640048d68713de54df368d2495cba0a. 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/QM6N22267079.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfc132b45156b262f95df09c658c2428c4ff0e70f5ffb6f4792e51974d35fee32. 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/QMDA72155367.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x95ea8f388296231eaf5ab62d762e69ec46d01ae79a74d72b4e4e718e808a807b. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/QMBZ92146488.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf20324f677ee8dd3b8c7d96774033d233176f62ff6fd9d50c2cda7fa56ac4c9f. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/UST8K1701389.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x84f33697f2fd207de916c7e9b0fb0e51c640048d68713de54df368d2495cba0a. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/QM6N22267079.