thumb|right|240px|"Cantus" (c. 1900), painting by Georg Mühlberg A cantus (Latin for "singing", derived from cantare) is an activity organised by Belgian, Dutch, German, French, and Baltic fraterniti
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 0x449ef58b7d881d0e79e34bcbe03bd53a2e23466d6ca194ddd347651a7a622497. 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/574344a7-8983-4462-9605-355420efb685.json and https://artists.proofprofile.net/proofs/artist/574344a7-8983-4462-9605-355420efb685.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 0x845b0b3ff6ce4336b888122a08c013e0cbcfc68424429e8c0c2afa1f47a3b286. Chain 2 (Bitcoin): anchored in block 960360 (2026-07-31T06:42:11Z), 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/NOMPP1910010.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb4cfa6d76f88444485ad96a2b5b0e3e6bfe3d67dd69edce9aabd1b1ddd6b3f05. Chain 2 (Bitcoin): anchored in block 960473 (2026-07-31T22:27:44Z), 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/NOMPP1910030.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa8a6a2792dbfd4a0870e8e8795d067cd7ad6b84c000611e416f1bf1b566f42b0. Chain 2 (Bitcoin): anchored in block 960381 (2026-07-31T09:50:11Z), 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/NOMPP1910040.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd428814c2a96ed3d2f22dc93a1cb04bfae6de4dc743bd15858251cd0a8e80f35. Chain 2 (Bitcoin): anchored in block 960163 (2026-07-29T23:20:38Z), 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/NOMPP1910060.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf843214e56da06617743be9be75d5465bd3b08e368cdb2501c24533c04ade68f. 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/NOMPP1910070.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x31e8865b351b09f279a60a647e954b70fe982e0df0572ae47edbf15384d16bb4. 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/NOMPP1910080.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb69e3aacf4de5086e0f49f664c50317b01b35cf671345a17132747b519e21554. Chain 2 (Bitcoin): anchored in block 960348 (2026-07-31T05:17:02Z), 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/NOMPP1910110.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5c7dbd925774c8adc8c7f36a9cb2a39ca38a85cb336d2271ceb75ea4f8af3e15. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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/NOMPP1910120.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2c4f8950543aa1531a4bd9867edb887eecd2e10524dafe7fb6a504e40ba13606. 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/NOMPP1910130.
Frozen - Original Motion Picture Soundtrack / Deluxe Edition
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd5ab8580c80e97f983206eff1b73fd4c300aa66d8d1cc92b0a0065913c7178ff. 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/USWD11366382.
Frozen (Originele Nederlandstalige Soundtrack)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd5ab8580c80e97f983206eff1b73fd4c300aa66d8d1cc92b0a0065913c7178ff. 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/USWD11366382.
Frozen 2 (Originele Nederlandstalige Soundtrack/Deluxe Edition)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1d132a00ce7ebb70e85585f8408e9e0306d5bbf86e90d80eca11f8a6c02626c5. 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/USWD11995066.
Frozen - Original Motion Picture Soundtrack
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd5ab8580c80e97f983206eff1b73fd4c300aa66d8d1cc92b0a0065913c7178ff. 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/USWD11366382.
Frozen (Original Motion Picture Soundtrack)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd5ab8580c80e97f983206eff1b73fd4c300aa66d8d1cc92b0a0065913c7178ff. 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/USWD11366382.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5af7d09a5ad1aeced7096349e7352e3b2e3fa880f5b636e9045e6e5ff076f1ff. 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/NOMPP1501010.