Voices in Your Head is a student-run a cappella group from the University of Chicago who aim to "push the bounds of contemporary a cappella." Founded in 1998, the group has consisted of both undergrad
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 0x85f6929d6023da97bfa0388562885b41536ba36e5df3559314ce39892502a440. Chain 2 (Bitcoin): anchored in block 953423 (2026-06-12T21:20:00Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/0e4069b6-14d0-43b9-aef7-87ed84a33192.json and https://artists.proofprofile.net/proofs/artist/0e4069b6-14d0-43b9-aef7-87ed84a33192.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 0x4027c738c770ce3e38cbcdd8936565b23535c0800d2f1c44a32dc5e4bf660f27. Chain 2 (Bitcoin): anchored in block 958060 (2026-07-14T20:39:42Z), 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/USE830924038.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe9ebec593b196818e1bdada8e597323d203b2cfb1ab19a75ae0267afebb20ab6. Chain 2 (Bitcoin): anchored in block 958157 (2026-07-15T15:53:04Z), 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/USE830941840.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd77f7be77d19c098e4d30e7769995c19bfaae21896da8611866b1ed394892256. Chain 2 (Bitcoin): anchored in block 958696 (2026-07-19T07:45:31Z), 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/USE831573658.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa4e1ef53fd6e858ea57ce721709dde05f3d6c45712e399c839a4607711b24505. Chain 2 (Bitcoin): anchored in block 958547 (2026-07-18T12:44:05Z), 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/QZ22B2054854.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2a372c177fafadc1f25150406f3494535bd3c8403be454a10d32430f6f042898. Chain 2 (Bitcoin): anchored in block 958251 (2026-07-16T06:29:25Z), 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/QZ22B2054855.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf57c9e312a530a38cd441c2449f5bcb2a2a1e76cc1d0ed4bd8a7b205129e4c7d. Chain 2 (Bitcoin): anchored in block 958601 (2026-07-18T19:27:02Z), 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/QZ22B2054856.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbb4ee1454fa2567cdc909c2f6d5f9fca9a728771d04d38473deb6d2859ce0536. Chain 2 (Bitcoin): anchored in block 956738 (2026-07-05T04:47:21Z), 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/QZPJ32306262.
Voices Only 2012 College A Cappella, Volume One
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9739aac36da3e44fd4466d2c93c7b683fe68e0d91a6ed6236c34c58ce9c04f30. 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/TCABI1211372.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x072c5f158ac9f4fe334e268588a209fd71d4b3ac4d053810f82db337e37df7c6. Chain 2 (Bitcoin): anchored in block 960220 (2026-07-30T07:28:30Z), 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/QZPJ32331471.
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
Voices Only 2013 College A Cappella, Vol. 1
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3203db7e44ab4ade2a174891b8ade30098fd0c0e6b0e3893448e02d938cac462. Chain 2 (Bitcoin): anchored in block 960216 (2026-07-30T06:39:12Z), 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/TCABP1338518.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7099d8135b513bb5877c91278d3dcc1d089427c7448a2c46dfc4c884af2c1408. Chain 2 (Bitcoin): anchored in block 960344 (2026-07-31T04:14:58Z), 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/QZPJ32232550.