The Central Puget Sound Regional Transit Authority, branded as Sound Transit (ST), is a public transit agency serving the Seattle metropolitan area in the U.S. state of Washington. It manages the Link
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 0x18f756f9ba3c6def0985959092b6c13a35b76aa8c810e8368fdc792f2bce059e. Chain 2 (Bitcoin): anchored in block 954705 (2026-06-21T13:42:37Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/f0f9a3af-bdad-45be-9d3b-4c65ac1ca315.json and https://artists.proofprofile.net/proofs/artist/f0f9a3af-bdad-45be-9d3b-4c65ac1ca315.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.