Duca Leindecker (born April 5, 1970) is a Brazilian singer, composer, multi-instrumentalist and writer, leader of the band Cidadão Quem. From 2008 to 2012 he formed Pouca Vogal, with Humberto Gessi
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 0x1513d0450bae4c1375e0f7fd936776b87ebf3b81d8f8734c5987f153e133fdf2. 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/7714991f-47fe-4f46-89fe-294060f0465b.json and https://artists.proofprofile.net/proofs/artist/7714991f-47fe-4f46-89fe-294060f0465b.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 0x5b2eb15b83756d0eb9d15735346c85fb03da26aed7f826e5f4323a207abc5053. 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/BRE1K1300005.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcf5f325a2f9d3874fd828a16c86399de9fff0b7ddc9bb778551fcd8a99e1c5b6. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/BRE1K1500002.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x78d3e2131c2ee7abd10f3dc47e450f92357df2fbb66c21486522e81bd350b9ff. Chain 2 (Bitcoin): anchored in block 956742 (2026-07-05T05:07:15Z), 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/BRE1K1500005.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe4d2797f3901dc3f6b2f7117c20ec5fbea93abcfe2ea97125ca9fb7a757d3b59. Chain 2 (Bitcoin): anchored in block 958808 (2026-07-20T02:49:15Z), 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/BRE1K1500007.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x55491425dc04ed58c3b79d71af08f04d8da107beb3085a416db3f19cc8ab6fc1. Chain 2 (Bitcoin): anchored in block 958876 (2026-07-20T12:15:48Z), 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/BRE1K1500008.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdb1eebf479f2df19c2916464758c3969a4b96b693fb915f640dfd227604599ae. Chain 2 (Bitcoin): anchored in block 959047 (2026-07-21T19:17:28Z), 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/BRE1K1500009.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdcf8cf3abb485bd71da7284fa560b83613030da2a4e91db4f93461c9b72cf5dd. Chain 2 (Bitcoin): anchored in block 958110 (2026-07-15T06:57:12Z), 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/BRE1K1500010.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa37af1244fe1a932b1f22e670087b8982d4a3759ae65ad715aa75e0c948ce659. Chain 2 (Bitcoin): anchored in block 958991 (2026-07-21T10:04:40Z), 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/BRE1K1500015.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd0808b68757b46ba39b1ed8870aa704c269bbd7cc9716b3a888e280ccbce061b. Chain 2 (Bitcoin): anchored in block 959047 (2026-07-21T19:17:28Z), 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/BRE1K1500016.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8f792c28d862750f0edba1af6f0d1a783a00bb81dd7e69631258de5ba4c11378. Chain 2 (Bitcoin): anchored in block 958234 (2026-07-16T03:46:09Z), 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/BRE1K1800004.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbc765e6fd6d2b1bb7a0ec91fd95f92fcc82a81b05d0e66a83fd2fecd1e30af5c. Chain 2 (Bitcoin): anchored in block 958935 (2026-07-20T22:08:19Z), 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/BRE1K1800003.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x679dbf3808524dcc437ca1c6cd36f5569a92658c022f831c27e7e75b69a887a0. Chain 2 (Bitcoin): anchored in block 957891 (2026-07-13T18:21:04Z), 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/BRE1K2000006.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x40c11ddd1c0413bd3cc255fa2e69fc1c18b206e399a27ab2f916347d176751eb. Chain 2 (Bitcoin): anchored in block 956634 (2026-07-04T10:04:33Z), 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/BRE1K2500015.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x654a56bbeecbcb1e6c703686c20b6f46a72ec361419988b2957096a6e07e0150. Chain 2 (Bitcoin): anchored in block 958415 (2026-07-17T12:50:13Z), 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/BRE1K2500016.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8883c5cd62d4064c459f46f01ce8f6876a74ef75605782107673a01ce7066e1b. Chain 2 (Bitcoin): anchored in block 958531 (2026-07-18T09:39:18Z), 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/BRE1K2500017.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x40f0dfa735a2bcb4805dda8edc3d3b00383d28bd9970c7391400154e06d01a9e. Chain 2 (Bitcoin): anchored in block 958650 (2026-07-19T03:36:41Z), 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/BRE1K2500020.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x372ae2facc235d79be6dc8b79186161600b280787d01367524fa773f46ea3fe9. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/BRE1K2500018.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfb3f1f2c3f0de8c7cac93e00088e2897ad7f50f55dd13355a23493ed711432b9. Chain 2 (Bitcoin): anchored in block 958607 (2026-07-18T21:01:11Z), 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/BRE1K2500019.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7f9f840ef2a7a440531d6f578c02a19323a559685b7fd182da132e295ba7071f. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/BRE1K2500021.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3d3753e10db8126be516d69137606c50fd944fc707a92643a4ba846f4a936b4e. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/BRE1K2500022.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbb0cf21d487dcc24bb85ef4be8ef1f63f0c48ae8992aff68fc2ced16c963a7eb. Chain 2 (Bitcoin): anchored in block 958853 (2026-07-20T09:11:53Z), 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/BRE1K2500023.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3a1b4766cb370c918b3fc1298cd1ba826c00818e0c63fb61db90221b91c85f5d. Chain 2 (Bitcoin): anchored in block 958870 (2026-07-20T11:19:23Z), 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/BRE1K2500024.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5e6fb759f83360bf32c2e0d9104664272ce064beca6d194651cd11e6319db66e. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/BRRGE1500468.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x83fab0db8ff4e2d27f35549ccbdb2e598947032a98a25e80a885f349b3c55717. 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/BRBOL1800006.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf6411c9ae9cdc16589186b58abd536aa27cf2f48b370800cc75b055c8e56f53e. 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/QZW9L2377832.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf6411c9ae9cdc16589186b58abd536aa27cf2f48b370800cc75b055c8e56f53e. 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/QZW9L2377832.