Carl Rudolf Hermann Friedberg (September 18, 1872 in Bingen, Germany – September 9, 1955 in Merano, Italy) was a German pianist and teacher of Jewish origin. Biography He was son of Eduard Friedberg
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 0xd8f0fcde828d0b5e52c34a991078429fa142fa8f55c4557634a61290d12ff633. Chain 2 (Bitcoin): anchored in block 953915 (2026-06-16T08:36:32Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1ae8c999-cb7c-4d75-8c79-ddc58c2b2b9d.json and https://artists.proofprofile.net/proofs/artist/1ae8c999-cb7c-4d75-8c79-ddc58c2b2b9d.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
Miniatures. Hidden Treasures of Heritage Piano
Am Stillen Herd. Opera Transcriptions from the Golden Age
Etude, Op. 25, No.9 (Butterfly) G-Flat Major - Duo-Art 5649
1. Confirm isrcCode identifies the recording in the pre-2022 source corpus and cc-db-prod record 2. GET OTSVerificationAPI → server-side canonical-record, hash, and attestation checks must pass 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. Confirm CopyrightID is the CopyrightChains transaction hash 5. If all match: the cc-db-prod record is independently anchored on Bitcoin at OTSTimestamp 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 0x084d666d9b96cf5f0f821b883e75d43cc443a0f3a6bc0477c4eb650641b1f007. Chain 2 (Bitcoin): anchored in block 960455 (2026-07-31T19:53:13Z), registered by our registry partner. The server verifies the private canonical record against OTSHash without exposing internal provider keys. Confirm the public ISRC, CopyrightID, and Bitcoin evidence at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/DEPI82437911 — a six-check JSON result.
"072 Hidden Treasures of the Piano": Orientale