Black Drawing Chalks is a Brazilian rock band from Goiânia, Goiás, Brazil, formed in 2005, by a group of graphic design students. History Black Drawing Chalks began with Victor Rocha and Douglas Cast
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 0xd3ec9f596d5540072922b7c50639781c643c2f0c8da54dc5dc03ca0c8880933e. Chain 2 (Bitcoin): anchored in block 953807 (2026-06-15T16:39:18Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/ee1ff2b9-8114-4046-b509-8144e904dc80.json and https://artists.proofprofile.net/proofs/artist/ee1ff2b9-8114-4046-b509-8144e904dc80.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 0xd2592c6db92a1429963811e13c583ecd141049f277143144e9657d2fe5c9c609. Chain 2 (Bitcoin): anchored in block 959001 (2026-07-21T11:41:42Z), 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/GBLFP1845333.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7445632623af4d217b6d658b8728120cfcc1aa47264672c7c927e99883cd9b3d. Chain 2 (Bitcoin): anchored in block 957759 (2026-07-12T21:46:51Z), 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/GBLFP1844718.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x71b98e382b012528fc79408ef7185d5983038f9dd5232f09e0e09e3bded82679. 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/GBLFP1844719.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x04ce6386c35b29e2c299be5b0beee2abe2a4df9ccc015b8a5ebe3f6a278aa183. 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/GBLFP1844727.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe36083458b17e396eadd3041be14a7b23f3f4a1097df78ea737c6c5a7991dd7e. Chain 2 (Bitcoin): anchored in block 958670 (2026-07-19T05:26:23Z), 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/BRZUQ1200019.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0b2755aefefdaa386e3d6b839c77b8fecbe8868b8e93bd38043a223da58d78fb. Chain 2 (Bitcoin): anchored in block 956422 (2026-07-03T01:01:38Z), 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/BRZUQ1200020.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc2b08c48c2021fc73bf76f851f68a46d22c330fe80a859a9a9af805101155fdb. Chain 2 (Bitcoin): anchored in block 959073 (2026-07-21T23:25:37Z), 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/BRZUQ1200021.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8a5671f084170e157792d49719963f2dd78bb66682714129f4238a919fa8725f. Chain 2 (Bitcoin): anchored in block 960166 (2026-07-29T23:39:29Z), 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/BXBAZ1700012.