Frank Boudewijn de Groot (; born 20 May 1944) is a Dutch singer-songwriter, known for "Welterusten mijnheer de president" (1966). Biography Youth Boudewijn de Groot was born in wartime occupied Dutch
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 0x5ed39d8d086c18cbeb8441638082a7b7993314d277eda90caa4a9cf16a91f2dd. Chain 2 (Bitcoin): anchored in block 953778 (2026-06-15T11:57:35Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/b9a3e4ba-f767-49bc-bb28-869033bf2ace.json and https://artists.proofprofile.net/proofs/artist/b9a3e4ba-f767-49bc-bb28-869033bf2ace.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 0x9a437c51e0c19004c2244f9a9d6cb7ac560015eca89fd82115fd63be0faddac7. Chain 2 (Bitcoin): anchored in block 958761 (2026-07-19T20:00:57Z), 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/NLWT12200002.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x94957fe93d97538c75006ed7ad974cad64e33b4dc4995beabe03f15e7ea4a97c. Chain 2 (Bitcoin): anchored in block 958808 (2026-07-20T02:49:15Z), 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/NLWT12400002.