Letard may refer to: Liudhard (), bishop of Senlis Letard I, archbishop of Nazareth () Letard II, archbishop of Nazareth ()
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 0xc6cb8cb2dd710e9e518d8366b9fb00f943e3e626dfb1855296081e3372d94247. Chain 2 (Bitcoin): anchored in block 953762 (2026-06-15T08:21:23Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/bac2f922-a786-4fac-847c-a1b0fc4adae7.json and https://artists.proofprofile.net/proofs/artist/bac2f922-a786-4fac-847c-a1b0fc4adae7.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 0xda80df8a63ac8f7a3c7133341ea03bcfca04081d4d63737fcb08dccf257fb0b4. Chain 2 (Bitcoin): anchored in block 957754 (2026-07-12T21:26:22Z), 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/QZK6P2427729.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa5f486013b9c7e8582dcc201350e6a2bb639cee4d45893cfbc6e26b722f6e2d1. Chain 2 (Bitcoin): anchored in block 958355 (2026-07-17T03:11:50Z), 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/QZK6P2447957.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfe78b4673aee74ef43564962d2138f2da6d0f3f830c4a624cabf47dee4083c35. Chain 2 (Bitcoin): anchored in block 957754 (2026-07-12T21:26:22Z), 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/QZHNC2418070.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdbc8989ebc15cf14d56fb4d8fee6e4b0820b42dffe96a5abd49b05b7187e90aa. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/QZK6P2447568.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x83dbb580fda19d331ab5d4ac6eda971840abe173fdeae3e3c8f0d65456cd263e. 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/QZK6P2480135.