thumb|Gideon Klein Gideon Klein (6 December 1919 – ) was a Czech pianist, classical music composer, educator and organizer of cultural life at Theresienstadt concentration camp. Klein was murdered in
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 0xb9018f56d08df05457ccc80842647122b13d93d192dd6ce5c7a12655c89dcd01. Chain 2 (Bitcoin): anchored in block 954631 (2026-06-21T02:46:24Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d0621d84-8f57-442e-8721-7f9ce0f00d8c.json and https://artists.proofprofile.net/proofs/artist/d0621d84-8f57-442e-8721-7f9ce0f00d8c.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Brundibár: Music by Composers in Theresienstadt
String Quartet No. 3, Op. 46: I. Allegro moderato –
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x08e1b44e39d4c075e8f609b1fa00cd2bff88b1e6c98b607ee5088fdb8f3046c3. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBAJY1397308.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x73919614aed0a86eaa5ab6efaf6499d192b80b2fc8cfd05589ed6b905c56c59a. Chain 2 (Bitcoin): anchored in block 957122 (2026-07-08T03:39:04Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLE422307726.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf2ac44b50cfd15a264702219dd7569f14e90a8f0c78bdc9998e4827d37ff9693. Chain 2 (Bitcoin): anchored in block 960317 (2026-07-30T21:35:24Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/CZA161200835.
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
Klein, Krása, & Schulhoff: Forbidden Music
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x38379c8dac5d97606c6128046c2a3030b9a89f1afe72f6ceb3baebbf5a3c2229. Chain 2 (Bitcoin): anchored in block 960389 (2026-07-31T10:20:10Z), 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/GBAJU0300060.