Hans Dulfer (born 28 May 1940) is a Dutch jazz musician who plays tenor saxophone. Biography thumb|Hans Dulfer (left) and Candy Dulfer (center) in 2022 Hans Dulfer was born in 1940 in Amsterdam. Hi
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 0xcdbcac1640ef8e7873a47ebe7d7c3cfacb061eae5ee3d0a7450b974b6145f0e5. Chain 2 (Bitcoin): anchored in block 953602 (2026-06-14T06:58:10Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/0ea68e59-c053-4064-b4ec-3639ca4c6604.json and https://artists.proofprofile.net/proofs/artist/0ea68e59-c053-4064-b4ec-3639ca4c6604.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 0x62f3d8ed33c80910a587fb44cfde19c6fc344f7bfffe45cc1c5260f8c6dcb43f. Chain 2 (Bitcoin): anchored in block 958714 (2026-07-19T09:51:44Z), 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/NLA279400605.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa3d10f74dc257349b27843fe3dd72f5284099b6e486e7894c6b0f525104842f2. Chain 2 (Bitcoin): anchored in block 958690 (2026-07-19T07:14:39Z), 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/NLA279400601.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x325fca614c79e5c4a77a8cb4863f49d7e80f75aafdbcc028ef35a581dad1d3a3. Chain 2 (Bitcoin): anchored in block 956772 (2026-07-05T10:01:46Z), 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/NLA279400607.
Big Boy, Dig Skin Deep (The Remixes 1994-1999)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb7ce556bf6886d4557ccfc14351aa3c0431416cdba0cfa2ce3f586729923257d. 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/GBCTF1000194.