ICA, Ica, or ica may refer to: Companies and organizations Empresas ICA, a Mexican construction company ICA AB, a Swedish retail food business, formerly named ICA Ahold AB Indoor Cricket Australia
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 0x20f0e14d9aeb37172bcfcb1b79d00f018d6dad79639bfc67b5ea61e300c1d865. Chain 2 (Bitcoin): anchored in block 953648 (2026-06-14T15:20:52Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/36504a76-f3dd-414e-82ab-962cc50f12be.json and https://artists.proofprofile.net/proofs/artist/36504a76-f3dd-414e-82ab-962cc50f12be.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).