Kardo may refer to: Kardo Bestilo (born 1976), Angolan writer Kardo Ploomipuu (born 1988), Estonian swimmer Cordău, village in Sânmartin Commune, Bihor County, Romania See also Cardo (disambiguation)
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 0x50c21211cfa2349317c9f70d3e5d146e35b0eea25c0fdb3f6e4760ed4e9be5ed. Chain 2 (Bitcoin): anchored in block 954667 (2026-06-21T07:29:20Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/df802cd1-c950-4498-9c49-293bd52a63dd.json and https://artists.proofprofile.net/proofs/artist/df802cd1-c950-4498-9c49-293bd52a63dd.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 0x5371b5444f95686dba4b28a08a945210bd6c1128eef3d3ba6fb0a926e1bb92cf. Chain 2 (Bitcoin): anchored in block 958582 (2026-07-18T16:47:25Z), 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/TRCFE2503432.