thumb|Mari Kalkun in 2017 (photo by Ruudu Rahumaru) thumb|Mari Kalkun giving a concert in her home orchard in 2020 (photo by Ruudu Rahumaru) Mari Kalkun (born 1 April 1986) is an Estonian singer and m
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 0xd35edf0163e43c636c86badd54bdb03b759ec336c946e44fcd8c1ddcc1e6e038. Chain 2 (Bitcoin): anchored in block 953408 (2026-06-12T19:28:13Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/168f08c5-f9b1-46fb-b641-a62c4168a5f3.json and https://artists.proofprofile.net/proofs/artist/168f08c5-f9b1-46fb-b641-a62c4168a5f3.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 0x11626ac27fd8dc84a806dbe7ab3c24aa8848f79354efe3d2c48ffc0a123efbbc. Chain 2 (Bitcoin): anchored in block 956560 (2026-07-03T23:28:02Z), 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/USHM91135091.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc74622d30a0df649f7abdafa49167190c94ef6f92682dc8c486ccc73da2c3076. Chain 2 (Bitcoin): anchored in block 958331 (2026-07-17T00:48:55Z), 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/USHM91135098.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x31dceee0f0d7b90c2dfb671ba3fb4e800a18257ea5c14aa6d848533f429cdcf2. Chain 2 (Bitcoin): anchored in block 958276 (2026-07-16T12:30:38Z), 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/DECW61700128.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x945d5819fa2e7f8c44108626be0729ac49fe0bbe57e0d06ecdffeb8006c9d7d4. Chain 2 (Bitcoin): anchored in block 956422 (2026-07-17T04:48:34Z), 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/DECW61700131.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbeeb5505816549199ceb222cb153a0128fa1f5ea352d214bead7b5e18e9746da. Chain 2 (Bitcoin): anchored in block 958846 (2026-07-20T10:35:05Z), 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/DECW61700135.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3d730117d5c2db061b5e6a6f6f2c16375ab6257eb517c5c083ef114fb782d8f7. Chain 2 (Bitcoin): anchored in block 956484 (2026-07-03T10:47:44Z), 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/EEIJ12000001.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x607d99ee4c2924eb746b99d859918dd982a0a28ac71b0cc6e5d8234d6661eb5c. Chain 2 (Bitcoin): anchored in block 958594 (2026-07-18T18:05:01Z), 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/EEIJ12000004.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3bfeb0a9da987383ecbf03f8ff016b260c38c87823f1563366aea0357ab7aec0. Chain 2 (Bitcoin): anchored in block 958331 (2026-07-16T21:55:37Z), 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/TCAEX2046904.
Shawanawa / Metsa Kene: Estonia Meets Amazonia
Munamäe Loomine (The Creation of Munamägi)
Lend Põhjataeva All (Flight Beneath the Northern Sky)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x3a962b8cead087918c093c6d261c536807ef25deb08cf56b743f65c9027a375c. Chain 2 (Bitcoin): anchored in block 958468 (2026-07-18T00:27:51Z), 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/TCAJG2549488.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x535515450f1a829f91a6cf6dd919e44cefe6c599dc282b354a1051652b33992d. 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/EEVC12000007.
Mõtsavele Mäng (feat. Mari Kalkun) - Remix
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x41481c45fb54f25e485c005289a5460fa7de5d2fda9bcd15979676261508b356. 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/EETI12100002.
Mõtsavele Mäng (feat. Mari Kalkun) - Extended Remix
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x67671c41a5db898284b44c3606899cb11de75e13b402d2473e10ee580d6ace92. Chain 2 (Bitcoin): anchored in block 956312 (2026-07-02T05:09:12Z), 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/EETI12100006.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf70ae633675b3647690032f46da10c1488941fcb07b618a8d304efb98a048faa. Chain 2 (Bitcoin): anchored in block 960240 (2026-07-30T09:57:33Z), 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/EELD32000001.
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 0xb7ed938ea3c334ba089f5aca67358154a1a7ac96b05b2d294d56f97b9a4a31dd. Chain 2 (Bitcoin): anchored in block 960241 (2026-07-30T09:58:01Z), 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/EEON12300004.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa56c6371d6d5b28448d7fc68704c7d7d019a7b772d89facd861cb84deca45b66. Chain 2 (Bitcoin): anchored in block 960099 (2026-07-29T11:30:20Z), 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/EEOA32000052.