A kontra (, 'three-stringed viola') is a Hungarian, Czech, Polish, Romanian, Slovak and Romani instrument common in Transylvania. Construction The kontra can be constructed new, but is most often a c
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 0xab07e8d61d9182e3eeaea8d201abef8cf51f7292dc18b57c86e701eb9aedaf96. Chain 2 (Bitcoin): anchored in block 953742 (2026-06-15T04:47:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/8e69df4e-643b-4441-8fd8-47a1e2b24887.json and https://artists.proofprofile.net/proofs/artist/8e69df4e-643b-4441-8fd8-47a1e2b24887.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 0x9a0a5edff21afd3177fc66b2a06764545fccafc9af9b61eedbffe0c9a008bd68. 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/FIWMA0500802.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3b88c5acf5f10f8bb47ae6808fb20f00a8767a6ac33a61f10d7377c6f38989a2. Chain 2 (Bitcoin): anchored in block 956422 (2026-07-03T01:01:38Z), 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/FISBA7700569.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd0b6eda2a24b2b419470984184df6fa8e0fc83e0c8345f3c6113f4ddb589351e. Chain 2 (Bitcoin): anchored in block 958935 (2026-07-20T22:08:19Z), 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/FISBA7700576.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9072e528befb0f7b9329d24508a96e5472ad9b36b3d99975cf4bb75dd26a2ccf. Chain 2 (Bitcoin): anchored in block 958579 (2026-07-18T16:26:17Z), 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/FISBA7700156.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x917ada4ad176d6385f4a78d9d1294aab568a6027bdd5f1fd288d1ce592fbe386. Chain 2 (Bitcoin): anchored in block 956476 (2026-07-03T09:04:44Z), 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/FISBA7800093.
70-luku - Suurten hittien vuosikymmen 40 suosikkia 4
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x13048ad9148a399842dee19480ab93b98e17ca86bfdebdbae415e3ed4acf4dd9. 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/FISBA7800094.