Anssi Karttunen (born 1960) is a Finnish cellist. Karttunen's repertoire ranges from the early baroque to living composers and improvisation. He has performed with many orchestras in Europe, Asia, an
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 0x61c65d7e6cc852f055114a362bad02063e85da185e4c14e2ff4c99f0af165d23. Chain 2 (Bitcoin): anchored in block 953812 (2026-06-15T17:06:52Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/f6781809-e66d-4051-9f10-e4b797737f3a.json and https://artists.proofprofile.net/proofs/artist/f6781809-e66d-4051-9f10-e4b797737f3a.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Saariaho: Graal théâtre, Château de l'âme & Amers