Quf or QUF may refer to: Quaker Universalist Fellowship Queensland United Foods, predecessor to Pauls (dairy) quf, alternate transliteration of the Hebrew letter Qof (ק)
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 0x287cb43e5144677a6a6d3b706ff582ae1992cd7981540a2d97afc7904fdff514. Chain 2 (Bitcoin): anchored in block 953407 (2026-06-12T19:24:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/050e1f3a-4cb3-42b1-8c42-3735b4484d10.json and https://artists.proofprofile.net/proofs/artist/050e1f3a-4cb3-42b1-8c42-3735b4484d10.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
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 0xcefa7eade6f1bbee38e763adbb29c02378c7c4cb5624b9043b538a25feffc906. Chain 2 (Bitcoin): anchored in block 958376 (2026-07-17T06:41:00Z), 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/USHM81959716.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1c4a24ff352b6d79696430a8aff95cff0e4519bc1bf16faa2758e83f19c0c51c. Chain 2 (Bitcoin): anchored in block 959100 (2026-07-22T05:29:55Z), 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/USLZJ1988563.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x52e01d6ff35e25c7eb9a6cd44957e0907714a08f7275560996a574795c6f69e5. Chain 2 (Bitcoin): anchored in block 959058 (2026-07-21T21:09:36Z), 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/USLZJ1989098.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5e7ca1146054c2b8d54aadf4f9544eb84ef3f1647bbc7dc57313a5d456937af5. Chain 2 (Bitcoin): anchored in block 956822 (2026-07-05T18:48:28Z), 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/USHM81179634.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x155bd7a7557f10ad79934226a284c95edaa2a1373bb0ce5232f2be5e9fc7009e. Chain 2 (Bitcoin): anchored in block 959105 (2026-07-22T06:33:30Z), 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/USHM81179635.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa800990c20e2c994d2b9c5977fc8fb16fc69a102e071ff52f8662019b6ed67ff. 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/USHM81179636.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0069718f65e083071eb3ee5d98ffc40a96cb4eaf496eb27f0bfb1992c3747653. Chain 2 (Bitcoin): anchored in block 959024 (2026-07-21T15:31:18Z), 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/USHM81179639.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x50f289ff1adcd062c4b44c649978e750e1b1e355aca1b05b6a6f64553ddecca1. Chain 2 (Bitcoin): anchored in block 956856 (2026-07-06T01:25:57Z), 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/USHM81179641.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x229428b23114fb897eedda9c566c3daacbdaae2b356ad8c860c5fbda2efb24d7. Chain 2 (Bitcoin): anchored in block 956402 (2026-07-02T22:05:07Z), 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/USHM81179643.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb4bff4442a7a2a742f9b38226e1f881511b4afec41cd9bcd12866d4923b16356. Chain 2 (Bitcoin): anchored in block 958943 (2026-07-21T00:27:37Z), 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/USHM81179644.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe3637d7d1d1b20067a1c6609812761b7253949c495e9653839ceae2c9e393e98. Chain 2 (Bitcoin): anchored in block 957747 (2026-07-12T19:35:06Z), 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/USLZJ1986043.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x76d8536aefa4cff71b5808a0665ce9dcbcbeb25c0b9c2d851b346567b78f9fb5. Chain 2 (Bitcoin): anchored in block 958905 (2026-07-20T16:14:34Z), 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/USHM91939295.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x55c22b5f4e689212f9d8101afbf2041e9dea6bafcf15a1a8d1fd2d3eaa56eb05. 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/USLZJ1988538.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1060df827cb3eb34ad65d8836c698b28eaf0d7156bb46100cb580bf6bfe77c72. Chain 2 (Bitcoin): anchored in block 956545 (2026-07-03T19:59:51Z), 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/USHM81959036.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xffbe6f9415818295e5e51934b3908ebe77be66aafd032ccd7436b980f5c10d8d. Chain 2 (Bitcoin): anchored in block 959058 (2026-07-21T21:09:36Z), 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/USLZJ1988492.