Sistars is a Polish pop/soul group formed in 2001. Their music showcases the vocals of sister vocalists Natalia Przybysz and Paulina Przybysz, and producers/composers Bartek Królik, Marek Piotrowski
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 0x9941fd80f51c9fce4b7be5a20f7bfedf6aefcd0d7a2eb5d14d874908a7059353. 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/f5f1d3c2-7502-474f-9a8c-2f583739f085.json and https://artists.proofprofile.net/proofs/artist/f5f1d3c2-7502-474f-9a8c-2f583739f085.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 0x45b04d2753e7f302ea83ee54957dad52277c48a4cae82966ea4eab2a6db5945c. Chain 2 (Bitcoin): anchored in block 960403 (2026-07-31T13:04:34Z), 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/PLA440500038.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x17f957b4e57539728c3a3c415d9bdae95e306e36214600d8ba5508c0d14cd059. Chain 2 (Bitcoin): anchored in block 959128 (2026-07-22T12:33:25Z), 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/PLA461600015.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9ca51c37ad2a71ce8486940a31f2761ba4dae7a3295dda31076b95a6aa631120. Chain 2 (Bitcoin): anchored in block 960117 (2026-07-29T14:28:24Z), 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/PLA811800054.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x17432c9bd533a6ed9cc14439b5546839d4b6cb1e090b3455dbef2921ad2892bc. 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/PLA811800055.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4029a48cd7a2f43e7574aeeac9276f46c1ac2be6d84671c5fa97b52e258000fd. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/PLA811800056.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfdf03cddf36ce9cff7dc072aeb5de7505d61296a5d1ad86bd63ffe246964832d. Chain 2 (Bitcoin): anchored in block 959128 (2026-07-22T12:33:25Z), 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/PLA811800057.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xecbfe32acdcecb91011020d75053848a2f4e14cd871a96e4c5855755bb8c11de. 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/PLA811800058.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x98c5e88f832600edd72e85ffbfb9d5fc1e9ff295087ebd47f4e2f6771e7e40e6. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/PLA811800060.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x317efc504847883423e182ebb4616b0c00a2fbf069e2046ffd436c8281b1a804. 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/PLA811800061.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xef01375ee12eeab81075a4344e2fe30a4f10253e9585d58d7dd84fe505852447. 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/PLA811800062.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4cd169a3ad7a17768d30cae8f9789245b25cd76955cf58340cdb6e114488a97a. 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/PLA811800063.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9dffd186d3e6745b8a8148ac67a5dfb70b10d952fa05b8ebb8279c7987112df6. Chain 2 (Bitcoin): anchored in block 960207 (2026-07-30T04:47:22Z), 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/PLA811800064.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x780a226a27dc6827645194c66e5ff97ec7fa776b0bf137eec39e046850ee56cb. Chain 2 (Bitcoin): anchored in block 959152 (2026-07-22T16:23:52Z), 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/PLA811800065.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5db8d63ec1e378b4e65709fe4b127c6f981ff7e1f693788d5e08b074e02f69bd. Chain 2 (Bitcoin): anchored in block 956889 (2026-07-06T06:56:49Z), 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/PLA811800066.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdbfe2ae00d9a1b4a9d59e54947604ec64e08e282dc476c835715884e59ab5c6e. Chain 2 (Bitcoin): anchored in block 960150 (2026-07-29T21:51:49Z), 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/PLA811800067.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8306a15ef8f113e6cd35681f1c0ac995b283d1cc592997a786b1f6b9234a950b. Chain 2 (Bitcoin): anchored in block 957064 (2026-07-07T16:43:08Z), 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/PLA811800068.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc55e043bbb590e9974a4843dae99bbe8cc0f7217ded069227fd029ffab7603a5. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/PLA811800069.