Klaus Mertens (born 25 March 1949, in Kleve) is a German bass and bass-baritone singer who is known especially for his interpretation of the complete works of Johann Sebastian Bach for bass voice. C
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 0x81ec4ba642d64772df284a99e9e91fa3814f62aa5b25b26013fb7179798e0eb0. 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/3b36ba6a-de78-42ca-8286-1970d5dadedc.json and https://artists.proofprofile.net/proofs/artist/3b36ba6a-de78-42ca-8286-1970d5dadedc.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Stölzel: Der für die Sünde der Welt gemarterte und sterbende Christus
Der für die Sünde der Welt gemarterte und sterbende Christus, Pt. 1: Mich vom stricken meiner Sünden
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 0x62d66e7f4eb972cd869d0a2743203a6a7501ace2265bbbe1c46d081520bb1ccd. Chain 2 (Bitcoin): anchored in block 960334 (2026-07-31T02:19:15Z), 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/DEB209756001.
Der für die Sünde der Welt gemarterte und sterbende Christus, Pt. 1: Der Gott, dem alle Himmelskreise
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf4a3ea3867b98afc7a9ae6bf63abb83f1dfebeb2a341aaf7e9763b09bc04b0af. Chain 2 (Bitcoin): anchored in block 960463 (2026-07-31T20:42:35Z), 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/DEB209756003.
Der für die Sünde der Welt gemarterte und sterbende Christus, Pt. 1: Gott selbst, die Brunnquell alles guten
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xc2de30d97d026fd26563468a2b98c6b963b82933e5fafb9e2682deeb98459d2d. Chain 2 (Bitcoin): anchored in block 960494 (2026-08-01T01:44:32Z), 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/DEB209756005.
Der für die Sünde der Welt gemarterte und sterbende Christus, Pt. 1: Drauf sagten sie dem Höchsten Dank
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8fd0e532f9d57800ea69f4484ee47ecd726e129baacf6b6078090d8ace8cd5b5. 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/DEB209756007.
Der für die Sünde der Welt gemarterte und sterbende Christus, Pt. 2: Ach Gott und Herr
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcdd8a825132e7d0baab159641e46a6eeaee95f17551cc37287a4df1c59167ae0. Chain 2 (Bitcoin): anchored in block 960478 (2026-07-31T23:30:38Z), 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/DEB209756023.
O Haupt voll Blut und Wunden (Arr. Johannsen )
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe41291608aea4cbeb7520fae78ac019f5ecca2cb26ba64c110957bdd3d700b25. Chain 2 (Bitcoin): anchored in block 960427 (2026-07-31T15:59:18Z), 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/DEB111200601.
Christi Mutter stand mit Schmerzen (Arr. Payer)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x46c55c60faa6b41ab17bbda5ffc4df58f90658abd28a825abe539c3f09997717. 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/DEB111200602.
Herzliebster Jesu, was hast Du verbrochen (Arr. Johannsen )
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe8f26c889a4fc5764c5be8a385a9e1957bd39bd8f654fb8dc186b20c2ce4dc24. Chain 2 (Bitcoin): anchored in block 960117 (2026-07-29T14:28:24Z), 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/DEB111200603.
Wir danken dir, Herr Jesu Christ, dass du für uns gestorben bist (Arr. Johannsen)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf99db43ca500ef4299badb39be293d67212b33cc7a5bdfd5631fc66357152a8d. Chain 2 (Bitcoin): anchored in block 960288 (2026-07-30T17:41:38Z), 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/DEB111200604.
Müde bin ich, geh zur Ruh (Arr. Johannsen)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x678cfa91fb4aeab436538035c164f79bdde19c4ea81a599ac2f310c00c10075b. 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/DEB111200505.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x22f03960aff71afd28763fa0e84dde6cf683c95ffd6df3b8d9d05ca4e2c70344. 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/DEB111200608.
Wahrer Gott, wir glauben dir (Arr. Johannsen)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd215cf96c6d20884312209ba693f3b2fa59dc2952019899ce71d27d3a3c1553d. 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/DEB111200609.
Ihr Freunde Gottes allzugleich (Arr. Johannsen)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x792207a208e6e864095cd86d01fe18d8a50a76f86d9bad93729724c6678ffa2f. Chain 2 (Bitcoin): anchored in block 960334 (2026-07-31T02:19:15Z), 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/DEB111200620.
Lobe den Herren, den mächtigen König (Arr. Johannsen)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9d1cdce7d6ca0f57b85731386d22b434f8a8a2e788d8c4a1fa2b10660cc4ecf7. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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/DEB111200621.
Johann Sebastian Bach; Geistliche Lieder
Herr Gott, nun schleuß den Himmel auf BWV 1092
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xeba3723cbc2a7dfb176991c1deeba324b71d8e9f1884b6d398195765c633f086. Chain 2 (Bitcoin): anchored in block 957120 (2026-07-08T03:22:41Z), 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/NLK172300001.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbca321e8efa8aec02ebf6d55993483e256582568242c634cbaefbb6ad998d23e. Chain 2 (Bitcoin): anchored in block 960397 (2026-07-31T12:24:41Z), 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/NLK172300002.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2b3fe23856d462983940b13d4dd2107d1001eb73f89c978cfee78dcfbcbcd80e. 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/NLK172300026.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x703ac777a2b8ac22ce8ad4954818c8ee0d197e4288347a8a4fdfeed2280b22ee. Chain 2 (Bitcoin): anchored in block 957145 (2026-07-08T08:56:20Z), 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/NLK172300028.
Telemann: Komm wieder, Herr, zu der Menge der Tausenden in Israel, TWV 2:12
Ein feste Burg ist unser Gott, BWV 80: II. Arie und Choral - Alles, was von Gott geboren / Mit unser Macht ist nichts getan (Bass / Sopran) - Live
Bachkantate, BWV 80 - Ein feste Burg ist unser Gott (Live)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2be5207bcc8178a398d3e2f8dc92fe94e60d0f13aba773f8cf59dd53f2bda021. 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/CH9211700114.
Ein feste Burg ist unser Gott, BWV 80: III. Rezitativ - Erwaege doch, Kind Gottes (Bass) - Live
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x121b51962544a1db743a93ee0fe0b9966d71039fb653f371d15c95e9bc5c5393. Chain 2 (Bitcoin): anchored in block 960334 (2026-07-31T02:19:15Z), 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/CH9211700115.