C2 or a derivative (C-2, C2, etc.) may refer to: Mathematics and physics C2, one of the common notations for the cyclic group of order 2 C2 differentiability class C2 or , the complex coordinate p
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 0xfba167508ed676e127e7202b90118a2ce8ca54b3b1a0831844a3cbd9468c3aa8. 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/f434f234-3fa6-463c-b416-ee0f9e4a9480.json and https://artists.proofprofile.net/proofs/artist/f434f234-3fa6-463c-b416-ee0f9e4a9480.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 0x3e735d7af38c9647375dd9b5c25b2d9ee23343ea4f1d5cdc6f3065c023bcc7ea. Chain 2 (Bitcoin): anchored in block 959087 (2026-07-22T02:05:55Z), 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/QZES92362336.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd35bd466ff5da8bf70e8716599472a2f8f1ad666dca6d9f6a7d532733b159e21. 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/QZHNA2331627.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc3c2a1d8021d5cc45dfa3bf0e7c6b26ab8eb256da723813d09f6c015085ff4b7. 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/QZK6H2343938.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb4aec0b1e939ba35fe55e87bc1a4d691704af679f6d4f7eddb5a8b1cfe129ad4. Chain 2 (Bitcoin): anchored in block 956856 (2026-07-06T01:25:57Z), 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/QZTBC2374634.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5cdb1764d9489f4b76770140472f34ac6b1d78e029b0cbfaec0c043b098c21ec. Chain 2 (Bitcoin): anchored in block 958197 (2026-07-15T20:40:29Z), 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/QZFZ72405852.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8d2ac9655cfec6f46a5729638a0f2a8b7d591b3f2c83baf03a0ce89981daf7cd. Chain 2 (Bitcoin): anchored in block 958153 (2026-07-15T12:03:04Z), 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/QZNWU2487364.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6d369512836fb099a1cb2fb1d4d50685a99f81cacc9fa9808bfb80693ba7be7c. Chain 2 (Bitcoin): anchored in block 958749 (2026-07-19T15:48:23Z), 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/QZZ782445418.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xad247cbb1637632ca817dbd907eda9eadd4a28dc24633949f4c415cc802db68f. Chain 2 (Bitcoin): anchored in block 956856 (2026-07-06T01:25:57Z), 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/QZZ7M2431509.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdd5be5858ae2911d247384b097571151568b1115332aa185aee2c8541cbbefaa. Chain 2 (Bitcoin): anchored in block 958776 (2026-07-19T20:11:59Z), 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/QZZ7M2431508.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x16bd5b6cda91b98c8bef6b9519e17470906be03af63ff3ed2f1cfec87d6f3963. 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/QZZ7Q2428610.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe8250ff6bfaea916fd6fc39f9ef3fcdb88b3f21510a08dbdbc8cdef605325210. Chain 2 (Bitcoin): anchored in block 958538 (2026-07-18T10:30:13Z), 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/QZZ7W2405881.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4ffe74936e09213e7ee970c7f98c76ebbf28735ff2a7b0fadd9eea4fbd30fa55. Chain 2 (Bitcoin): anchored in block 958951 (2026-07-21T02:01:41Z), 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/QZZ7W2405880.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb950c35e768cb1932110d03da6be27c05c00f00dae7cbb99c1002af8543b6285. Chain 2 (Bitcoin): anchored in block 958436 (2026-07-17T16:42:22Z), 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/QZFZ32558739.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1206246b85132e92c07f2229ceba7405baf39483aa20f84b255fddf6266ec8a4. Chain 2 (Bitcoin): anchored in block 956375 (2026-07-02T16:51:38Z), 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/QZFZ32558740.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5419cee78d9b98e62ca30ad0929f1479e28986f466ca1df87536130a4d3d09b0. Chain 2 (Bitcoin): anchored in block 959114 (2026-07-22T08:41:42Z), 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/QZK6F2563748.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe06a96aef39d7702f9ca200686e265c7abbde3928934edd151360277ff42b51b. Chain 2 (Bitcoin): anchored in block 958180 (2026-07-15T17:59:52Z), 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/QZK6F2565886.