thumb|Self-portrait taken 1913 Carl Heinrich Louis Held (1 December 1851 – 17 April 1927) was a German photographer and a pioneer of photojournalism. Held was raised by relatives after the death of h
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 0xcb928e004c3f9ebac4596f590078f273a4745a73ce7e696dd394d54141ecada9. 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/fdb3d248-55a3-4b67-b628-dcb0b054215b.json and https://artists.proofprofile.net/proofs/artist/fdb3d248-55a3-4b67-b628-dcb0b054215b.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
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 0x49a4478d84d56c707f15c056e3940fa326aaa1964d3bad0fbeed272f3aa11529. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEUM71804483 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x01cb671f5186b4eb5293d3d2f192a0413e916b87dc677bff5b5a96f69157a8c1. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEUM71806868 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xeb952651e386dd3be7333cab893823ad0001f3723076211cedea841a142c1fb9. Chain 2 (Bitcoin): anchored in block 958714 (2026-07-19T09:51:44Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEUM71902918 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x01cb671f5186b4eb5293d3d2f192a0413e916b87dc677bff5b5a96f69157a8c1. Chain 2 (Bitcoin): anchored in block 958885 (2026-07-20T13:01:04Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEUM71806868 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5004828af2be830af32cd1d8928c2aca3e844ee10988d52b9b94f44abddb83af. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEUM71903817 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe37f1b1bbb12466d2ae52ca1fa0e294bb7975d13b8e8436b11d80c9296c1a122. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEUM71906748 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xeb952651e386dd3be7333cab893823ad0001f3723076211cedea841a142c1fb9. Chain 2 (Bitcoin): anchored in block 958977 (2026-07-21T06:27:23Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEUM71902918 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe87cf4771a39314a0dc56fcfb62fe7dfddc423ba957144a3ebe61bd4d63c07c2. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800942 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb781e7403b5270efb8d28b3fd61aab9e06d419f99db30a9cd5ae0eda0d3d3495. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800953 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xddc2606936dc3509d04bd848eacb957c5d966a9146792019967a019e19620516. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800944 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x61d45bdaec71b7a67ce74e9673f6839ed97ce464ea06210bba168dbf65ae0ee8. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FR10S2236597 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x218a324d69f479d42cf690797a3bfb1283603f6a1d5c19eba1bd30e93664ac70. Chain 2 (Bitcoin): anchored in block 958625 (2026-07-18T23:11:57Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800946 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7b8bf41313549ab7d49a63c2b75ca729b9bef4d4bc8890856d4a4743d3e8956b. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FR10S2359213 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe87cf4771a39314a0dc56fcfb62fe7dfddc423ba957144a3ebe61bd4d63c07c2. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800942 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb781e7403b5270efb8d28b3fd61aab9e06d419f99db30a9cd5ae0eda0d3d3495. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800953 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc9ac10f2e2757e2550b7e60f8c22c2cf8d87cbbc3d52e25ac93beb67256bb7b5. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FR59R2279446 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x873420285df6b897d64350e80b14d84be4b8b629e9fadf0fbb33f603a6b75547. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRX202272897 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x61d45bdaec71b7a67ce74e9673f6839ed97ce464ea06210bba168dbf65ae0ee8. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FR10S2236597 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xce08c27f85a92b37cdef4a68f242a9f8ab60424a91a4ec96a3950249d0b53d1d. Chain 2 (Bitcoin): anchored in block 959132 (2026-07-22T13:20:46Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DGA082244579 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1992fa166461f81e4f939b623fe0c273ebf05eeb91e7fa29961c570cc74a8ab0. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRX282399513 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8f80b51815c6e3b58062d4f4fa298df87541ebe2d2b5ee2c751a09c72d147f44. Chain 2 (Bitcoin): anchored in block 960207 (2026-07-30T04:47:22Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRX202257195 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xddc2606936dc3509d04bd848eacb957c5d966a9146792019967a019e19620516. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800944 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf7dcb79af36b51452ab43d8e47379c6fa531bf4e7bd7ec26bd60da1b2073f6b4. Chain 2 (Bitcoin): anchored in block 957050 (2026-07-07T14:41:13Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRX282358465 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x41606dffb53cf910839f3951c8a06db898211d51223731246ad084d147247b4b. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800951 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xee39a7c25f2f59f64b6a463154ae870add049e00f1add1f21154575819893c67. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FR59R2201525 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3a1843d9df21a4690a65aa95e8cd6b0acc1090b7dbe59d47ac4950a523c8b9ed. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800949 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7b8bf41313549ab7d49a63c2b75ca729b9bef4d4bc8890856d4a4743d3e8956b. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FR10S2359213 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x218a324d69f479d42cf690797a3bfb1283603f6a1d5c19eba1bd30e93664ac70. Chain 2 (Bitcoin): anchored in block 960164 (2026-07-29T23:23:05Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800946 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6105cc3acb1f7c11c6e00e99974659faf6b0c113e1514bff6d7e7fdc422f7450. Chain 2 (Bitcoin): anchored in block 960276 (2026-07-30T16:01:17Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800945 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x40e90697a434fe96d89918b8132f813139150861b6185ae2eae378b8fb795c7a. Chain 2 (Bitcoin): anchored in block 960337 (2026-07-31T02:51:48Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800952 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x53f2268a8884021577f757879e5063c69adb3a3bda627816ad5a9cd7837ea1bd. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800948 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa5833ded953eb5e80df86ba28fe5c509aa7aa0c14c69111cda8cf92b31b14988. Chain 2 (Bitcoin): anchored in block 960240 (2026-07-30T09:57:33Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800943 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcacf473111408852c2dd4a66ffde38ce97d4ca5c17e27e45220f754452cd8eb7. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRX202388182 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x37088875c4054aa1d40e8205b3a412e946f099861a4b5cbd02b5e13b89e9d497. Chain 2 (Bitcoin): anchored in block 960284 (2026-07-30T17:23:26Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/FRX282399514 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8f159e7c2402d99e147b4e2404f6a849be404da34003011b9d8c1a39458b53f4. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEBL61800950 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x821994974633d5377e6c638917ab0ee92a81894b9b4a868d2bec6afe0b1305aa. 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/CH7812407178 — a six-check JSON result.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6c02b9ffa02f45dbd43c945a5a8b62bc444217df3aa52a142b91a9cb35af2dbb. Chain 2 (Bitcoin): anchored in block 959043 (2026-07-21T18:40:26Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/CH7812412786 — a six-check JSON result.