Entrañas () is the third mixtape by Venezuelan electronic music producer Arca. It was released for free download on 4 July 2016 through Arca's SoundCloud page and MediaFire. It features contributions
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 0x0d1a19bd7ca014abfdfbde648334ba426fae7d9f7ba3e23f70362e763cd52790. 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/efa41729-ce55-439d-b057-a75b43135337.json and https://artists.proofprofile.net/proofs/artist/efa41729-ce55-439d-b057-a75b43135337.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 0x61931df0478f02cc743f36eb2a7901da5b6167d56066fee56b20d9cf0a73bfa8. Chain 2 (Bitcoin): anchored in block 960485 (2026-08-01T00:10:46Z), 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/QZMHL2404578.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x968dd0e8822a9b277d308d2a96aaf24f644fe3e93be6334b289d5750fe896869. 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/QZMHM2465974.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7961848ecbf0b7c0fe67fa02a434099de76fe3376b0d7bfbec2058ba84e168fd. 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/QZS642484486.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x84296c9b779826f597d971cb1b8167fb52020316cafab3481f5f2a6d66aa21f4. 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/COAB11900175.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa352a9e9102c9751a2375942fbb0a1dfc8df28e492ac0264038b16027f8f0c64. Chain 2 (Bitcoin): anchored in block 960435 (2026-07-31T16:33:26Z), 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/QZS672257915.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5ecd941a57cec991e2bcc150d7f460b444430b1feb54cf4073113699ee2f20c2. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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/QZMHN2395953.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x41f2face34907d081358e4ef18296d2452b48f60d045efbda115d86409c5100f. 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/QZS642211347.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb0ada8984d22d8219b5617f72015d6a84859d042d28e05cf815727ede563b331. Chain 2 (Bitcoin): anchored in block 960277 (2026-07-30T16:10:47Z), 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/COAB11900099.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xee3b943d150b3f4b6a661179ec084ae5da4f2cfe8b8bf3e1be1a5f24e49afbc9. Chain 2 (Bitcoin): anchored in block 960121 (2026-07-29T15:22:21Z), 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/GX3Q92116710.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3aed64cbc13f09c32be9c98b712b96bb10b1b1a2ce8fd648096e3c719d95c47a. Chain 2 (Bitcoin): anchored in block 956312 (2026-07-02T05:09:12Z), 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/GX3Q92101212.