William Kroll (; 30 January 1901 – 10 March 1980) was an American violinist and composer. His most famous composition is Banjo and Fiddle for violin and piano. Biography thumb|"The Elschuco Trio", i
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 0x9d380c3b0453749ccd09eb8f3f157b263c7d9f1a99cfc37a3e8d167be47787b2. Chain 2 (Bitcoin): anchored in block 954533 (2026-06-20T08:57:02Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/a3e14a69-16bd-4db5-9678-a93288778d89.json and https://artists.proofprofile.net/proofs/artist/a3e14a69-16bd-4db5-9678-a93288778d89.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Kroll: Banjo and Fiddle (Orch. Kennedy, Lenehan, Messiter)
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 0xc81c850aceaa209424d1009b248af5fcdce7b101fb9d5fa32d86f2f55dd5e103. 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/GBAYD9800392.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1f563abead5ca41e470821a91dac415166a1a0de82f02e41ccc68c01dfaee0dc. Chain 2 (Bitcoin): anchored in block 956891 (2026-07-06T07:16:32Z), 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/GBAYC2400576.