A2K may refer to: Access to Knowledge movement A2K (America2Korea) A2K, a type of baseball glove sold by Wilson Sporting Goods
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 0x404214b28bfbc35c40147293eb4c6d582807486b27483dfbdca6d079d9323e4c. Chain 2 (Bitcoin): anchored in block 954533 (2026-06-20T08:57:02Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/a415f105-f254-4ddd-98f3-e2d2f4382e91.json and https://artists.proofprofile.net/proofs/artist/a415f105-f254-4ddd-98f3-e2d2f4382e91.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).