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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0d1a19bd7ca014abfdfbde648334ba426fae7d9f7ba3e23f70362e763cd52790. Chain 2 (Bitcoin): anchored in block 953808 (2026-06-15T16:45:15Z). 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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x968dd0e8822a9b277d308d2a96aaf24f644fe3e93be6334b289d5750fe896869. Chain 2 (Bitcoin): anchored in block 957145 (2026-07-08T08:56:20Z), 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 957124 (2026-07-08T03:53:27Z), 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 0x5ecd941a57cec991e2bcc150d7f460b444430b1feb54cf4073113699ee2f20c2. 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/QZMHN2395953.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x41f2face34907d081358e4ef18296d2452b48f60d045efbda115d86409c5100f. Chain 2 (Bitcoin): anchored in block 956349 (2026-07-02T11:34:59Z), 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 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.