thumb|Library card for the National Central Library in Taiwan A library card is part of an integrated library system which can refer to several cards traditionally used for the management of books and
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcd46e0bbd1893ceec46b4d6ca869d0156c9c18e2629c4dc4f2f837c7c6e97952. Chain 2 (Bitcoin): anchored in block 953627 (2026-06-14T11:43:04Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/2f80866d-37a9-4e70-8e4a-724720564f4d.json and https://artists.proofprofile.net/proofs/artist/2f80866d-37a9-4e70-8e4a-724720564f4d.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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbce025c2a9687a52da1d79c521cdc92659e94eacb099b2072127d60a4b94d66c. 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/NL4BA2300021.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6818b6c50865ffe97c0a76ddf8e7b2a813bc88e495e6fc66ba8a632d3ce0d1c2. Chain 2 (Bitcoin): anchored in block 957124 (2026-07-08T03:53:27Z), 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/NL4BA2300022.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1241a035dead6b85ed05d5e243f93f74c272ab4799fdf7aeba12ac2c6a27cf2a. 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/NL4BA2300024.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6818b6c50865ffe97c0a76ddf8e7b2a813bc88e495e6fc66ba8a632d3ce0d1c2. Chain 2 (Bitcoin): anchored in block 957073 (2026-07-07T18:39:05Z), 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/NL4BA2300022.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbce025c2a9687a52da1d79c521cdc92659e94eacb099b2072127d60a4b94d66c. 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/NL4BA2300021.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1241a035dead6b85ed05d5e243f93f74c272ab4799fdf7aeba12ac2c6a27cf2a. Chain 2 (Bitcoin): anchored in block 957124 (2026-07-08T03:53:27Z), 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/NL4BA2300024.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1241a035dead6b85ed05d5e243f93f74c272ab4799fdf7aeba12ac2c6a27cf2a. Chain 2 (Bitcoin): anchored in block 953536 (2026-06-13T17:25:41Z), 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/NL4BA2300024.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xaa6579d6a7d2972cdcc67c65839d25a1b1e39f17dee1719665600d5157d73469. Chain 2 (Bitcoin): anchored in block 957122 (2026-07-08T03:39:04Z), 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/NLS8K2300002.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xaec2c617fdaa79d066cb1d33afac79d1e64d523a710fb2d657e3b31439f0e0ed. 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/NLS8K2300001.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5fcb2781cc56f8a8b0a0a61ce910b897b3cd1ff1aa4ff77b5f52236bb8ccbe83. Chain 2 (Bitcoin): anchored in block 956349 (2026-07-02T11:34:59Z), 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/NLS8K2200001.