Sonova Holding AG (Phonak Holding AG before 1 August 2007) is an internationally active Swiss group of companies headquartered in Stäfa that specializes in hearing care (hearing instruments, cochlear
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 0x69f9c2115b7d2e9637b68a35fb2b00c8244881243dc9e51ec8d450583fc85774. Chain 2 (Bitcoin): anchored in block 953933 (2026-06-16T11:13:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1e267428-e3ed-4e94-a581-91414ddb18e0.json and https://artists.proofprofile.net/proofs/artist/1e267428-e3ed-4e94-a581-91414ddb18e0.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.