Ota Petřina (4 June 1949 – 11 July 2015) was a Czech guitarist and songwriter. During his career, he primarily wrote songs for other artists, including Marta Kubišová, Helena Vondráčková, Václav Necká
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 0x1e8a6e8dedfb56a821894488090d484fdbca753e0a999dbfd891fe5c140adfd7. Chain 2 (Bitcoin): anchored in block 953842 (2026-06-15T22:22:30Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/e11dded3-920c-46a9-80c8-48f74de5ad67.json and https://artists.proofprofile.net/proofs/artist/e11dded3-920c-46a9-80c8-48f74de5ad67.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 0x903e21c69c7e4907038673ccdd2e32362c68e79cd7e6b8c443aeedc2060c75fd. Chain 2 (Bitcoin): anchored in block 958428 (2026-07-17T15:15:14Z), 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/CZA167800271.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x47191cf99a4c10d4c26f80b3b1b23aa6c42727dbb9f6427e1f73406b2183e480. Chain 2 (Bitcoin): anchored in block 958920 (2026-07-20T21:01:44Z), 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/CZA167800272.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd36884334f376fff18a31c8f0b1f4d854e0f869d95fd8228cf7f35b4f4e2d51d. Chain 2 (Bitcoin): anchored in block 958991 (2026-07-21T10:04:40Z), 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/CZA167800273.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0eb7b205bb4db2a956c153fb3659be22b158dc9d6d5287dc2e6d248166549ee0. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/CZA168100363.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x45091310078fd01eb1bd352fcbae95d5951bf5587065a92f9a4ea09154407c1f. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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/CZA161701585.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2b5c06ccdb8c0e9105f9ff25f47171b01bf1b66197d429398e943aee68711212. 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/CZA161701587.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8eae3019a348a0e878db9367c8d1ad14bd3e0601e804e9d6ebb63ad4de04e5c6. 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/CZA161701590.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6cc2272783b63a9fd4e935142110c78a90bbf17d4460bbd8f1f32403102ec57e. Chain 2 (Bitcoin): anchored in block 957118 (2026-07-08T03:20:19Z), 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/CZA161701595.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x005824845c6d0bef273b1c49d84376b86e27b5e3e04974b8332c59ccee57050b. Chain 2 (Bitcoin): anchored in block 960473 (2026-07-31T22:27:44Z), 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/CZA161701586.
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 0x86c0942594a3fb6d060e832185f4f36fba8fb25e5080530d2eb99b2267c32ac6. Chain 2 (Bitcoin): anchored in block 960349 (2026-07-31T05:23:41Z), 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/CZA161701589.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdd15682932941f8965776b92e6c8c2981eea6bfb92e8ab50f490919c165020c2. Chain 2 (Bitcoin): anchored in block 960456 (2026-07-31T19:53:57Z), 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/CZA161701591.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7a87a903f225f7aa5f450923de3bbc683975a9537919c7b7306aabb594cc96f2. 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/CZA161701592.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf895d17f2964a8a64751cf45e3abe5450c76ef7ad57a7942d9a6deed9fb1d880. Chain 2 (Bitcoin): anchored in block 960468 (2026-07-31T21:25:57Z), 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/CZA161701593.