upright|thumb|The Knife-grinder by Goya shows a man using a portable grindstone. thumb|Two lumberjacks using a hand-powered grindstone to sharpen an axe during World War I A grindstone, also known as
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 0x6db355148dc0403deac356ac2cb9a9c4a2911ec5f5532b164b744aa9f0f7e190. Chain 2 (Bitcoin): anchored in block 953727 (2026-06-15T02:33:01Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/903f8dc0-cd46-4e43-b922-1da2e2d6cdcd.json and https://artists.proofprofile.net/proofs/artist/903f8dc0-cd46-4e43-b922-1da2e2d6cdcd.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Football Withdrawal (feat. Counterclassic)
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 0xd969d30e12594bf60404567681042b3cc590074d75ad37f1125623d8ccb7d7a8. Chain 2 (Bitcoin): anchored in block 956474 (2026-07-03T08:56:35Z), 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/QZES71809321.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x520ee4ec54a3217bec113bdfb297a6c3ac3e8e8d860487315c70b3a831147e28. Chain 2 (Bitcoin): anchored in block 958319 (2026-07-16T21:44:25Z), 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/QZK6M1901592.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdd15c455cfa40fd0b5258046450968d2325c529778eb070f754397b8067cb5c4. Chain 2 (Bitcoin): anchored in block 958621 (2026-07-18T22:59:44Z), 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/QZK6M1901595.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1425288c9f06fcd03b69ec560a7eb80b7f2fe8fe8b814f65abc9e5c5f071693d. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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/QZHN92102501.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x84c48b4380020f00ccf9e614707c4566ee4c32905e5f188560ff28580d2cc9ca. Chain 2 (Bitcoin): anchored in block 956375 (2026-07-02T16:51:38Z), 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/QZK6P2191725.