Jan Keizer may refer to: Jan Keizer (referee) (1940-2024), Dutch referee Jan Keizer (singer) (born 1949), Dutch singer and composer
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 0x06f68354e402c4ba96a796a47f0432e9e55fc840bb9b2c274d73f60c595667e2. Chain 2 (Bitcoin): anchored in block 953407 (2026-06-12T19:24:56Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/469fa1ff-6bca-4725-9595-f02b9b036fcc.json and https://artists.proofprofile.net/proofs/artist/469fa1ff-6bca-4725-9595-f02b9b036fcc.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 0xf31df4ae412e9a0d91adcb1801cf61429b01f9a5ca2b2313d72238f23ac6b4aa. Chain 2 (Bitcoin): anchored in block 959008 (2026-07-21T13:14:05Z), 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/NLD760100004.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6656b6beae7dbc551b10f2b83278afadcc5b0acf38e6285c60327b108040b76a. Chain 2 (Bitcoin): anchored in block 958987 (2026-07-21T09:04:56Z), 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/NLD760100005.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x052eccec07a977cf1c5da7311aba378d21599941f0b493db7a5d987075511186. Chain 2 (Bitcoin): anchored in block 956891 (2026-07-06T07:16:32Z), 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/NLD760100008.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xee4f1b9a5d1d83d7d9dd1d78454a7535476e38d721c3e22b4c079f36c295dfe9. Chain 2 (Bitcoin): anchored in block 958943 (2026-07-21T00:27:37Z), 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/NLD760110022.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf2a8d903c1202a9a77b21b28d70798b5c3aa618bca3981deda927787d36d0bbb. Chain 2 (Bitcoin): anchored in block 958541 (2026-07-18T11:37:54Z), 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/NLD760110023.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb2732cb1e09316f2bb35404203b996f6bd49428d3acec18ed179c6efc923c0a6. Chain 2 (Bitcoin): anchored in block 958535 (2026-07-18T09:42:49Z), 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/NLD760110024.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2b1f5be9fee0e8e18ef41987097b3679e238beb4846602c8dbba5710149ae70d. Chain 2 (Bitcoin): anchored in block 958931 (2026-07-20T21:15:01Z), 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/NLD760110026.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd037f4c22c7444db6c4e218aa73de8ab35023dfc43ab2bcad22a283c83c65dc8. Chain 2 (Bitcoin): anchored in block 958444 (2026-07-17T19:12:23Z), 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/NLD760110028.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x382b6f06b42f932cda8ff2e67988d1c948c924f6cf7f37d995d18bb92c0330ee. Chain 2 (Bitcoin): anchored in block 959008 (2026-07-21T13:14:05Z), 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/NLD760110029.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x932a21a7b3c85ae9850d2f932e29ac60939d4b8b60db7c44e65d7af33a4558ef. Chain 2 (Bitcoin): anchored in block 956725 (2026-07-05T01:12:41Z), 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/NLD760110030.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1f5a0c033e73f786b5ee38c69039c7c7b78de4839d9b6477c1362cca400aaccd. Chain 2 (Bitcoin): anchored in block 956826 (2026-07-05T19:27:56Z), 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/NLD760110031.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc0aff4784ee9e7866d6081a6cbd68803f7a932aeb57feaa88d38b2227e48ef49. Chain 2 (Bitcoin): anchored in block 958234 (2026-07-16T03:46:09Z), 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/NLD760110032.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe5b2be8b7a85d17fab1359913a2308cd0c96ed37a471b18e11cb7cf6e6f42f62. Chain 2 (Bitcoin): anchored in block 958991 (2026-07-21T10:04:40Z), 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/NLUM70700549.
Zie ik jou dan is het zomer (zomer versie)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb338a9285afc5972d098f2cfc45dfb024c7c14231c55db1acc8063ce229a577d. Chain 2 (Bitcoin): anchored in block 958300 (2026-07-16T16:14:30Z), 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/NLUM70900241.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1b6b59c89e492cd5668f27e3430088a1c5fbe1480b61b5c02d3dc7b71639b65b. Chain 2 (Bitcoin): anchored in block 956474 (2026-07-03T08:56:35Z), 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/NLA241007757.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf465ecb9c50f53d01011b7152b7620ea5eea21ee4f70572566c735b9ae7b647b. 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/NLA241007756.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5ef720cf7f49931eefde815282c613d67c9380f68ef4c38b630bafc810663aa5. 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/NLK072400144.