Hooja is a Swedish electronic music duo. Consisting of Hooja and DJ Mårdhund, the duo's identities were unknown the first years. In July 2023, their identities were revealed by the Swedish newspaper A
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 0x470f6c04a4128d30da3b0158b21f47d352d7ad28ca0e6dfa2e8ebccf5a003d17. 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/944e3ffe-2319-417b-8780-d5154cc56bdc.json and https://artists.proofprofile.net/proofs/artist/944e3ffe-2319-417b-8780-d5154cc56bdc.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 0x31d70fad35b8e57e171d39f46a9f2aebfcd5fd4a03762a5243d35c406f9f6362. Chain 2 (Bitcoin): anchored in block 953528 (2026-06-13T15:41:10Z), 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/SEYQH2400101.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcbf0aab85e6ffef483962d60b72226120dc2d3c0c7881f69a0dd34f8528c6387. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/SEYQH2300201.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x505bf27814786db8b85973d8255d4d3dc7db8642ae64808c1e4057185a2b1f02. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/SEYQH2400301.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8193e90408ddbb052b132247a17abcdb28cd477cb131d7a6d7d5cc7845580bff. 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/SEWLR2102401.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6a9ad61cf2b017c23abb62a6d5120873b181ef8be98af407ff23e8a773b04db2. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/SEYQH2401101.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf632a18882bdf1198380bdde07b8f3a5705a8beb4d24b0c3908f7870e3bfd63a. Chain 2 (Bitcoin): anchored in block 953513 (2026-06-13T12:47:07Z), 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/FIWMA2500023.