A placard is a notice installed in a public place, like a small card, sign, or plaque. It can be attached to or hung from a vehicle or building to indicate information about the vehicle operator or co
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 0x66dbed832707f3de718fb73e9c2777f0a74cee65da0310d9b104ed309d0434cb. Chain 2 (Bitcoin): anchored in block 953625 (2026-06-14T11:37:06Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/23b4724d-64fb-4f68-9370-009d42c1b00b.json and https://artists.proofprofile.net/proofs/artist/23b4724d-64fb-4f68-9370-009d42c1b00b.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 0xc7f8e5187cdc8f11d541c213a7dc06b1591c71aa174901241b1246a2ea546763. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZHN72498152.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x98d81b53dfa7cc57106a90b936206d9b7117f824e08b55d18df3c34d7fd45e1d. Chain 2 (Bitcoin): anchored in block 958673 (2026-07-19T05:38:28Z), 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/QZMEQ2476484.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfe0b896598c74902b9b8553cfd5bd1859439d6bc95e5c746ab2025bf9ec86410. 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/QZTAW2420988.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x46bfdd3a62487754042dd0fa3618cee39af27550761c313bc25b038e5a4acaeb. Chain 2 (Bitcoin): anchored in block 958058 (2026-07-14T20:20:34Z), 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/TLVEM2468159.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb0d51add876de5398e6a7694adfa25f94833945240dbc718a71a67d5accdbd82. 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/QZWFK2428384.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7cb03250c8a8601947739301b7edf100142ec040447d414669cb9bbfd8ab03c8. Chain 2 (Bitcoin): anchored in block 958666 (2026-07-19T05:00:30Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZWFT2450130.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x46f778f5955da589e698953cf97c27e78faac4c42ec040fa481e6b316c6cdd7b. Chain 2 (Bitcoin): anchored in block 958300 (2026-07-16T16:14:30Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/SE5BU2577532.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xef13df6c781278312b02c573e292620dcafdb283bd8ebe02e5293a1af8c7def9. Chain 2 (Bitcoin): anchored in block 957558 (2026-07-11T11:36:38Z), 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/SE5BU2596771.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x06f5b2fdd40c11641c527d148c9f08691fe4c1b7ad04cb7bf4a9779e71cd9b96. Chain 2 (Bitcoin): anchored in block 957576 (2026-07-11T14:19:48Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/SE6XY2516953.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3dbcdf7bf1ca06fbba7d6bd425cd2710de2d3e6894df1cdcf7b64d2621fc0cb0. 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/QZK6G2594398.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x47aa0535d9ce8123e0862f655c9e4b800d4abe986d6690f23358ddb279de4125. Chain 2 (Bitcoin): anchored in block 958286 (2026-07-16T12:43:37Z), 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/QZNWQ2577970.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6b05a34be05e2181837f2da95b3f2981fc58ad2c677e213e718b62f9dd9b8211. Chain 2 (Bitcoin): anchored in block 958808 (2026-07-20T02:49:15Z), 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/QZNWX2548478.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1c217c1a7c6d342d583da024c8b1849d3007e733e81a286d2784480a4aa3d860. 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/QZNWZ2552466.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf39f62246fb45e95e4f60e2c6fc19d3e6e89c941350911af8aabb056c5091aaa. Chain 2 (Bitcoin): anchored in block 957785 (2026-07-13T01:55:31Z), 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/QZTB62596283.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7d08693d46724e68ee33e4a887cb2a5ae91addf9e655d2fe2e41c41ab9fa9d72. Chain 2 (Bitcoin): anchored in block 958300 (2026-07-16T16:14:30Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZTBE2591431.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb61c0bbebea56cb82f06ee2189e1ab7d7854d91e30c8782f7eeb0c43ae9019a5. Chain 2 (Bitcoin): anchored in block 959128 (2026-07-22T12:33:25Z), 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/QZPLR2567635.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1f52a1eb9d49affccb1e2308dac4d5776852630775f8a8371c44666b27700077. 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/QZWFK2569410.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5453f29849815c9613a12aa31b8aa85c35624db468fcbdc6bb93b44cff4d31b4. Chain 2 (Bitcoin): anchored in block 958808 (2026-07-20T02:49:15Z), 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/QZWFK2569411.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x825b3cc0a6d2313b7fc048d9c1435b25dde26c59196f958a547448f3c0bf62b3. 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/QZWFK2505163.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8e21e6e5c9917eb5be24f0b240418e3e528de43458ab27fe6d529c767d08ba1c. Chain 2 (Bitcoin): anchored in block 958838 (2026-07-20T07:01:21Z), 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/QZWFL2578366.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb8c353a0798d82edc3c5949b12c4167c2905a1c743f1f71a61744287c353b691. Chain 2 (Bitcoin): anchored in block 958812 (2026-07-20T03:24:09Z), 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/QZPLS2425772.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x47faa4703c19af8ed8e3d8c03cc8402d81018b94bb610e205b1483500ed69108. 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/QZZ7K2546169.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x089805ec9492956b5c4dce5f3be83e1ad538dc763f8689b3e6541641d5844d73. Chain 2 (Bitcoin): anchored in block 959118 (2026-07-22T10:01:58Z), 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/QZZ7S2536534.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x677647924b20568f6e751a22642fd4e3ec2d7ec56dc264c5b5307bffb4111462. Chain 2 (Bitcoin): anchored in block 956738 (2026-07-05T04:47:21Z), 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/QZZ7U2540777.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0ffdfa05309e9fb84999309bf4581c90f2cd0452d9e6cff769b5789a17d6ed01. 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/QT3F82589694.