Lars Jacob Jack Vreeswijk (25 January 1964 – 3 April 2023) was a Swedish ballad singer, song lyricist and composer. The son of troubadour Cornelis Vreeswijk, he followed in his father's footsteps and
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 0xad764bdf5a2a01f31d9e88851d74e47967f55b1a51f778337492e8ce59c9caad. Chain 2 (Bitcoin): anchored in block 953612 (2026-06-14T08:22:11Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1649ce24-901b-4cf3-8fd6-b4d4e48af0fc.json and https://artists.proofprofile.net/proofs/artist/1649ce24-901b-4cf3-8fd6-b4d4e48af0fc.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 0x4432783f976c675d34a05cab77b4946cb12763db500e5038caf711eb8b0da7fb. Chain 2 (Bitcoin): anchored in block 956545 (2026-07-03T19:59:51Z), 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/SELAA0301611.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb0e68884f45f4f8ed812093203cd8d79dd7186cae481df5d83636674376639c1. Chain 2 (Bitcoin): anchored in block 956856 (2026-07-06T01:25:57Z), 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/SELAA0301605.
Tjuvjägaren (Original Motion Picture Soundtrack)
Brev från kolonien (feat. Jack Vreeswijk)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xadbbaf468802558a36ead997be66514fcc6fcdb96c0696edf2020acb529c0926. 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/SEPQA1400597.