Free city may refer to: Historical places Free city (antiquity) a self-governed city during the Hellenistic and Roman imperial eras City-state, an independent sovereign city Free imperial city, s
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 0x4a12f1c1b04df491310f66a034133c1b4bc2926687fd907f0be45bc24b6f0320. 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/57f37886-af2a-4f64-b6bf-f872d29a3267.json and https://artists.proofprofile.net/proofs/artist/57f37886-af2a-4f64-b6bf-f872d29a3267.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 0xfe0ae0378ea1203ec53fe5d2a3432efe2f30db10744197141a3f2955d62b12df. Chain 2 (Bitcoin): anchored in block 958428 (2026-07-17T15:15:14Z), 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/ES71G1803142.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4ce6d3cdf515379298afefa27dcdaac21c344e8ae86e8d588e878b5dfb638b19. 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/ES71G1803150.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x678c3df150cf5bdacc8d4dd41e1a0059f431da40b5366c9585b9a520d74c01de. 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/ES71G2001640.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8cbecc2ece75514183979634ad118acf8502e181545db5cfbc6365068deacea5. Chain 2 (Bitcoin): anchored in block 958728 (2026-07-19T12:24:55Z), 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/ES71G2001642.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xaac66ef8b718d3e1d344284e0311b3814258ec192913b48ed294a715cec4b11e. 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/ES71G2001645.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x63b1efde6502008ca6f243ed791ca13d8c75180027a3a3bd02f99f6571147d9b. Chain 2 (Bitcoin): anchored in block 957888 (2026-07-13T17:43:59Z), 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/ES71G2001650.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3066a62b7a7d35c2872521a3beca5718b22707d423de13aed68accc289fefad9. Chain 2 (Bitcoin): anchored in block 957888 (2026-07-13T17:43:59Z), 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/USA2P2114416.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xef61da510c549cce4ef9e35fcaf8c11dcd5da3af66f63b648a01090e1186c60a. Chain 2 (Bitcoin): anchored in block 958917 (2026-07-20T17:53:56Z), 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/USA2P2115505.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x001c3dde01068295331c3f1fe1607a548490c85b51c650044a071b94ff78e911. Chain 2 (Bitcoin): anchored in block 958742 (2026-07-19T14:09:34Z), 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/USA2P2146090.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x57199d892baf47da922ef3cd725ad569549c8c75a36508c6af6580dfd28e96cc. 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/USA2P2120827.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8d0e2580149208d589b4bb224d58ee2ca10bd2ae3ccbec31aba5469fe5bdee95. 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/QM4TX2419800.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x14ac8a9d3d8832904bdf2b0e26350068aa7b327a4968122c42435411107a14ce. Chain 2 (Bitcoin): anchored in block 956545 (2026-07-03T19:59:51Z), 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/QM4TX2421525.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5c4eb68d77a251325bdbc3072daf7f060e12fdf398e81dab25839a8066ce65f9. Chain 2 (Bitcoin): anchored in block 959058 (2026-07-21T21:09:36Z), 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/QM4TX2421531.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2bfc42b1b3ea3b0b7f833437f9f3fbaf5ac9daf579792695e4e37f51505e0bbc. 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/QM4TX2421535.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x43c98f41a6898ff69a8f4c1460cc549f2ec90752f0f59d36576600ff9ed7ae61. Chain 2 (Bitcoin): anchored in block 959069 (2026-07-21T22:32:59Z), 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/QM4TX2421530.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa96f3eea1b347513fdd66909d568849b23a68b679a8ce0e7d0dc08c8ac3d4661. Chain 2 (Bitcoin): anchored in block 957888 (2026-07-13T17:43:59Z), 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/QM4TX2421533.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x49be4b9e09266af9bdec13d10e9e6a75c6b12f21402cc99f84a694844bb96d75. Chain 2 (Bitcoin): anchored in block 958571 (2026-07-18T15:39:25Z), 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/QM4TX2421524.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd49eded59ae12f807e2437478959fbb708e28a22a905571a34e5d480565d496d. Chain 2 (Bitcoin): anchored in block 956889 (2026-07-06T06:56:49Z), 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/ES09S2200002.