thumb|right|upright=1.35|Barbershop quartets, such as this US Navy Band ensemble, sing four-part pieces, made up of a melody line (normally the lead) and three harmony parts. In music, harmony is the
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 0xae571fda7d68b7b0d15d7615efa5f5e11613111384f77f02b64a21bef7c249de. Chain 2 (Bitcoin): anchored in block 953645 (2026-06-14T14:31:42Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/3f73551d-0481-45cf-bc0e-b8db6fd8578a.json and https://artists.proofprofile.net/proofs/artist/3f73551d-0481-45cf-bc0e-b8db6fd8578a.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 0x3127341d0a6b7322a9534ce29ff63d830672dd269f78a880c355e967693e8c61. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/GBRD51800057.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe464d15097c215dc1298bc11bf03c04c94a91bd325f8a737c7f73072115455d9. Chain 2 (Bitcoin): anchored in block 960220 (2026-07-30T07:28:30Z), 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/GBRD51800229.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4899ce210289258612214392d3c69715d5e3d2e7436dd7f35fdab2c8842ae485. 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/GBRD51800230.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x15447591a7f2d1a676266ce7ebce82b634b8151e13b54b04c73165045d9f4b72. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/GBRD51800439.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x656531dec341e099abbe8c89196c3bec87fcf5663ae15411218f6e7a6fe27965. Chain 2 (Bitcoin): anchored in block 960294 (2026-07-30T18:46:00Z), 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/GBRD51800440.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3cc4e4237c3e4d6303be286626236a09ec0bfb21993297aed9b2fa7c2c289291. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/GBRD51800441.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x20c976df9b29b11710828713b40f3969c1f510e40a2615ce0711ad67508230fb. Chain 2 (Bitcoin): anchored in block 960236 (2026-07-30T09:37:10Z), 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/GBRD51800442.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb05dca4d11a0f44a87fb357d2dc2826f3577817c79e99d133e1706141cf8c80f. Chain 2 (Bitcoin): anchored in block 958942 (2026-07-21T00:24:07Z), 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/GBRD52000042.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x43f0e90efbe986d971b01eb0b17af34cddc282353ab6b7cb58e7f39ff014d5f1. 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/GBRD52400399.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x915bf12f28766f6b219c75cde1f3c2c86e02662c6f257751f84db19539bb027b. Chain 2 (Bitcoin): anchored in block 958224 (2026-07-16T02:28:43Z), 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/GBRD52500037.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfb8cfd5b6c7fed1f809d921ee88db39ac655e75c5e31df965b52255b4824df45. Chain 2 (Bitcoin): anchored in block 958134 (2026-07-15T09:14:08Z), 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/GBRD52500038.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x06075a97eb102a7c1e5c552db5cb80f8fe709e5773f58514c21014b9fc6c57a2. 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/GBRD52500039.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd04a377b1b73538a2a8edf7436125618ca307fce4963331a6376651c9fbd79e4. 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/GBRD52500108.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfabeeb3c144117d6daa936b74a79dc3b0c275b07c654e15a9708ae3ad9ff95bf. Chain 2 (Bitcoin): anchored in block 956474 (2026-07-03T08:56:35Z), 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/GBRD52500110.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6499a11e0db5873edc9d7acff0a0d31b18b70d20daf7d5cb818edf1e68ce9bec. Chain 2 (Bitcoin): anchored in block 958647 (2026-07-19T02:36:14Z), 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/GBRD52500111.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x01dce2c7d7592869dd548ad0634582afa36dc396580fb06cd78c672f4029b7df. Chain 2 (Bitcoin): anchored in block 960327 (2026-07-31T00:26:26Z), 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/DEKB72076664.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdf48aae047dd656a793be4bfd92e5db2734f438fb18b96d805f11ad27426ce4b. Chain 2 (Bitcoin): anchored in block 960327 (2026-07-31T00:26:26Z), 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/UKN6K2002878.