Jan Jansen may refer to: Jan Jansen (cyclist) (born 1945), Dutch cyclist Jan Jansen (historian) (born 1962), Dutch historian Jan B. Jansen (1898–1984), Norwegian professor of medicine Jan K. S. Janse
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 0x7fceaec5524fb84e6c5c14bf5c73dd11cf2b95a22dc3996267017c2edcb8b094. 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/90395a4e-d1ff-4fff-b615-5e051a7dd4eb.json and https://artists.proofprofile.net/proofs/artist/90395a4e-d1ff-4fff-b615-5e051a7dd4eb.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Divertimento No. 5, Kv 439b (Kv Anhang 229): Polonaise
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 0xafe3768c3aaa88123fbe90b5fbe3287817b3826dc3ac75d141a3c11565d08235. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/NLN580512875.
Divertimento In B Flat Major Kv 186: Allegro Assai
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xee8c78f80f68c717bb5313c4731dbbe03a6ba4a09f2def6c41318ccf6dc0fd31. Chain 2 (Bitcoin): anchored in block 960138 (2026-07-29T19:35:34Z), 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/NLN580512895.
Divertimento No. 6, Kv 439b (Kv Anhang 229): La Ci Darem La Mano (From Don Giovanni)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1b92ec3cd08c5826ad5e7d84f060b282d57815dd506e53d14208a2979152d2a2. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/NLN580512879.
Divertimento No. 4, Kv 439b (Kv Anhang 229): Allegretto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1dc829991d4510913bfd22d9cf3283cd561a9700e3182a65c82d1a299cd9d1c4. 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/NLN580512870.
Divertimento No. 5, Kv 439b (Kv Anhang 229): Menuetto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x767f7abe2db36a3da5e790bd4945e56f1565e6ebd96a1059a261f5bf9a561e05. Chain 2 (Bitcoin): anchored in block 956304 (2026-07-02T03:55:08Z), 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/NLN580512872.
Divertimento No. 5, Kv 439b (Kv Anhang 229): Romance
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x02075c69a6d04cb5680737d1a798c32182b2a7403cc169e670788eeb8231fb1c. Chain 2 (Bitcoin): anchored in block 959107 (2026-07-22T07:19:23Z), 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/NLN580512874.
Divertimento In B Flat Major Kv 186: Menuetto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x76cdd6d1d6172cb1cda1d947806b971cb721c07777c9708023799b590ec3a384. Chain 2 (Bitcoin): anchored in block 959163 (2026-07-22T18:47:29Z), 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/NLN580512896.
Violin Concerto in D, R.234 "L'inquietudine": 3. Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x85b3b5d3d9e112f533398ff0d93d48cd73a41148f2fadd75627ca5b5c0e63891. 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/GBBBA0900600.
Divertimento No. 4, Kv 439b (Kv Anhang 229): Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7ea4826742ec7dcfab55123c20ce90c12fdeb68345a17d3f5fc9e4a8afa1185c. Chain 2 (Bitcoin): anchored in block 960448 (2026-07-31T18:48:12Z), 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/NLN580512866.
Divertimento No. 4, Kv 439b (Kv Anhang 229): Menuetto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x752b04541924ec13dd3e037f3aaf5832745843d702f64186533d5ba359262497. Chain 2 (Bitcoin): anchored in block 960455 (2026-07-31T19:53:13Z), 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/NLN580512868.
Serenade in E-Flat Major, K. 375: V. Allegro
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbcdb838240cd462cddb03f9aeb749b6105114e4dcbe8c42e71947d82fb9b22dd. Chain 2 (Bitcoin): anchored in block 957124 (2026-07-08T03:53:27Z), 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/NLY331410614.