Emptyset is a Bristol-based production project, formed in 2005 by James Ginzburg and Paul Purgas. Ginzburg and Purgas say that by working across performance, installation and the moving image they are
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 0xd7fdb20b763622535ce91c922e8035a3a3ba395c4bc89952c48b57859be8c974. 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/a5b5e297-1a8d-4f7c-8e26-affd7648b2cb.json and https://artists.proofprofile.net/proofs/artist/a5b5e297-1a8d-4f7c-8e26-affd7648b2cb.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 0x493ed948cfea61b00faad232c9e6581a91a93cd630200bb6d59dbdd71584358b. Chain 2 (Bitcoin): anchored in block 956474 (2026-07-03T08:56:35Z), 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/GBGXC1520011.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7c53fa3a6df26e8ce03fd67dd640b4a074019df2b71af303c85e8adb956f7538. Chain 2 (Bitcoin): anchored in block 958340 (2026-07-17T00:53:26Z), 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/GBGXC1520013.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7eeba058dd25069098d3fb1b556e623b32b526ae1c6806a006d6efa94a7f1ab9. 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/GBGXC1520014.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7da4d9eb827bef5197cc9a71084570ac33f2c643aaf7740500b092e726cc24ef. Chain 2 (Bitcoin): anchored in block 957796 (2026-07-13T03:24:42Z), 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/GBGXC1520016.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4d452ec61ad1b15312cddd0506f8e197d25f6df0b2ce88d55c45c41567731ac1. Chain 2 (Bitcoin): anchored in block 959103 (2026-07-22T08:20:15Z), 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/GBGXC1520017.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x77c28a923202602234137f7c170f18652d135504f30f6188ee3ec86c05cd16ad. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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/GBGXC1520018.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8c224d95aac0d3be75512eeebc7f4483d69af756a70ba0a80caeec7a31dc46c2. Chain 2 (Bitcoin): anchored in block 958543 (2026-07-18T11:58:44Z), 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/GBGXC1520019.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe971268ccb7b854f6d19d88d003fad24a4ac02709b32dbfe5d7a2ccd1c701eb3. Chain 2 (Bitcoin): anchored in block 956396 (2026-07-02T21:01:51Z), 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/GBGXC1120004.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4f6889fa915165ecae742568f52a05b09558cc5d43b8c09b93a5db5994c5cad7. Chain 2 (Bitcoin): anchored in block 958340 (2026-07-17T03:09:36Z), 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/GBGXC1120006.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd2f040f085c265fbbd9752e4272b19124de6a90bcc96770998c810b9996ec518. Chain 2 (Bitcoin): anchored in block 958913 (2026-07-20T19:51:22Z), 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/DEAS91200082.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4cc5bc7ee01dfe2feac819383111c06b9ee52dfc5a934d3a822e04a3edb72972. Chain 2 (Bitcoin): anchored in block 958390 (2026-07-17T09:35:49Z), 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/USTJ21742901.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2e4bc54000a80de70c0405b23d502b1f6ab5b9a19e06ad7573d916d7f8207eb8. 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/USTJ21742902.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4ff61569d0f3c7028f1c2407deee923fadc861b480f07d15b7e9f24aeaac6b6b. Chain 2 (Bitcoin): anchored in block 958668 (2026-07-19T05:16:11Z), 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/USTJ21742905.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3b18c1c984e83f4519fed064fd0cc5f023ec1800e0182aaafdcc5ffb3688e5ec. Chain 2 (Bitcoin): anchored in block 958208 (2026-07-15T22:40:25Z), 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/GBGXC2320030.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa74c0049c25ecc0abb6ac6107c8085b0ebbbc3031776b6e3ac8457054fe9ef7b. Chain 2 (Bitcoin): anchored in block 958480 (2026-07-18T02:58:58Z), 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/GBGXC2320032.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x656d34fd67bc89111be85aeff67ba5afdbcf4a965309d72653f7dfcf0ce956ea. Chain 2 (Bitcoin): anchored in block 958689 (2026-07-19T07:11:11Z), 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/GBGXC2420045.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x55af4655bd8664e4f366ca24550af958a7781bb8653606a0e6b08e42591a3ffb. Chain 2 (Bitcoin): anchored in block 956474 (2026-07-03T08:56:35Z), 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/USTJ22563103.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdd8d1255b30f2e24e718f20a176814fbab2bec0f4f39404bf424b4ec379b5f74. Chain 2 (Bitcoin): anchored in block 956420 (2026-07-03T00:42:11Z), 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/USTJ22563106.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x543b05dd5a0b5f7a34dcdce6e5960774088aea7f9f14694ae8140caba5730a2d. Chain 2 (Bitcoin): anchored in block 957851 (2026-07-13T11:26:33Z), 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/USTJ22563107.