200px|thumb|right|Copper duit coin from 1735, with the VOC monogram on the obverse and the crowned coat of arms of the Province of Holland on the reverse. The duit () (plural: duiten; - "A small Dut
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 0xfb205286482216b571e2ad6a34803672d266e7b2886da8b0abad190b16c3583c. 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/a50b49b1-a150-49f7-820a-04e53f1c8699.json and https://artists.proofprofile.net/proofs/artist/a50b49b1-a150-49f7-820a-04e53f1c8699.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 0xdd8e2d930d506e147a550c95f7924e1a80f23be0e8b32379ea8cf6ff05c2aa08. Chain 2 (Bitcoin): anchored in block 958104 (2026-07-15T05:34:05Z), 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/PLC071603005.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8a5700f6ccfd6c63cc2cca515bd2db1dcb626692c42028fec20f111a95e12c87. 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/PLI292100254.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x37f0e2115f05284e6ce57494bd374fe6456c4e4a02c6d2f319f9e088899e5769. 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/PLI292100251.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8a5700f6ccfd6c63cc2cca515bd2db1dcb626692c42028fec20f111a95e12c87. 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/PLI292100254.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x37f0e2115f05284e6ce57494bd374fe6456c4e4a02c6d2f319f9e088899e5769. Chain 2 (Bitcoin): anchored in block 953528 (2026-06-13T15:41:10Z), 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/PLI292100251.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1ef3962becf67a225f6ea65e1e6ff0b62846ebbf0c246bf58a564d5e7a4ef949. 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/PLA681401518.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb0d4400d7e5cb426cb43979817d0ee9e1c418c45015a401ebf6f23169d6438f7. Chain 2 (Bitcoin): anchored in block 957041 (2026-07-07T13:25:45Z), 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/PLA681401508.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6f4d9c8bcf1be15f25701dec165f04b5dcd6206cab7a48146fda5c8403188157. 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/PLV402000713.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6f4d9c8bcf1be15f25701dec165f04b5dcd6206cab7a48146fda5c8403188157. 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/PLV402000713.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0fc5c8cd00d458475ea1daf604c193c867d96c6ddbd79405aaf5e328724d3586. 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/PLA681401607.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x39c18f3add24b791d56b49e432078d6d554a261168c0d5987bd6c5fc25908de6. 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/PLA681401626.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4dcf9ad4a44f2dbd0c9362c03673363af08cab6e2a67b28b7b996cfeef3d90e9. 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/PL39L2000001.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x019d04013ad33eeab6c863029d2949820e9e6de97625f53298dda2df607961ef. 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/PLA681802233.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6cadcac263f7453a973fdc74e68ac7d3967456073bb2714a0b51bfb08c168e80. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/PL02P2101007.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5cf4bf856ab19c7a007384ba2fb97762a107f1fce250e540514b3f2aa04e138b. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/PL02P2101014.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6cadcac263f7453a973fdc74e68ac7d3967456073bb2714a0b51bfb08c168e80. 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/PL02P2101007.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5cf4bf856ab19c7a007384ba2fb97762a107f1fce250e540514b3f2aa04e138b. 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/PL02P2101014.