Berthold Klemens Possemeyer (born 20 May 1951) is a German baritone in opera and concert, and a voice teacher at the University of Music and Performing Arts in Frankfurt am Main. Career Possemeyer
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xac545b8d2093618d5b7745643d208002be2cc76339389d1a1b49b0771abfdbec. Chain 2 (Bitcoin): anchored in block 954065 (2026-06-17T08:10:43Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/464b756b-b857-4c48-b6f3-48e00a7b7a70.json and https://artists.proofprofile.net/proofs/artist/464b756b-b857-4c48-b6f3-48e00a7b7a70.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Mendelssohn: Vom Himmel hoch. Kirchenwerke II