thumb|Sivuca ca 1960. Severino Dias de Oliveira (May 26, 1930 – December 14, 2006), known professionally as Sivuca, was a Brazilian accordionist, guitarist and singer. In addition to his home state of
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 0xa6be730b3329cb0fe754ec64a0d152b41c155dd400cc5c7f4570daf71731303f. 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/f260c1d2-c6c4-44af-ad3d-d7833a35c4ac.json and https://artists.proofprofile.net/proofs/artist/f260c1d2-c6c4-44af-ad3d-d7833a35c4ac.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 0xe824d14d57abb968d139eb1e4fd02836afd902a957a4395bb97059f0cb131ae3. Chain 2 (Bitcoin): anchored in block 960327 (2026-07-31T00:26:26Z), 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/BRKUA9205201.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x86fd09172fcc87772cdca7380f2f0d5a7f4a02f2789b2cd782a5a11e8c228d3f. Chain 2 (Bitcoin): anchored in block 960337 (2026-07-31T02:51:48Z), 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/BRKUA9205202.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xec9b092dae5a8ffc8f55cc3f9fdb91d0d213d68ca8b0960b5b31d5733d2e744e. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/BRKUA9205203.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbc24f670fcf043f1fe69081aa33de1d21e6e56c38d8746a6eeaf3eabf18a6992. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/BRKUA9205204.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0e3d01f8484acda2846e5716ff550b04857e1f4f2a23283b3911629b478dd3f9. Chain 2 (Bitcoin): anchored in block 960309 (2026-07-30T20:35:49Z), 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/BRKUA9205205.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x75f89cf2794541472301caef1827590fe79e3abc3844f0a0b4dcb89a872b35e2. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/BRKUA9205206.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x642d69618136200bce55fc038d7b26d2853faef3a3d1656a0356c604324eea6a. 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/BRKUA9205207.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x95b60599a6a57b1923f45925a9e41e2f784be3a16b852fd5939ccc405020c2b2. 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/BRKUA9205208.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x953a4ae1d2233b1961bf5cfc353fb72214fc902d99e16f4182dad9f32439d77f. Chain 2 (Bitcoin): anchored in block 960264 (2026-07-30T14:36:16Z), 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/BRKUA9205209.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x85f9e15a6e414ec62d6bfd0fd98ead6bee49ef7d9c7352d2f24dea5c616c23bd. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/BRKUA9205210.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x293c41fd10540806bc42fcc378efe333325d473abfe209eb1d6d05394fcf67ad. Chain 2 (Bitcoin): anchored in block 960473 (2026-07-31T22:27:44Z), 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/BRKUA9205211.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8300aeccf314e5c1e43ea32f9676ec8394581d3a3426743a5866c2728a0a6a63. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/BRKUA9205212.
Um Tom para Jobim (Arr. for saxophones and piano by Mitchell Toebben)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7644b015ef70eb49cecfc688798fac49533b4f1440982e684e92fcee22890fff. Chain 2 (Bitcoin): anchored in block 960150 (2026-07-29T21:51:49Z), 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/USPMZ2311601.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd953b12e187e158fc97f8cabffea35344164070f697c069b41db7dc390e1d348. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/BRSME0000336.