John Holmquist is an American animator, director, designer, and storyboard artist. He has worked on several episodes of Rugrats as a director and storyboard artist from the late 1990s to early 2000s.
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 0xdc1fae776d403bd0cc481756650d7a85329b15398937886cee0ca31a91355ebf. Chain 2 (Bitcoin): anchored in block 953625 (2026-06-14T11:37:06Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/28c8d003-5aae-44cc-958c-a1bac8dc5831.json and https://artists.proofprofile.net/proofs/artist/28c8d003-5aae-44cc-958c-a1bac8dc5831.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Cavatina - Highlights From the Guitar Collection
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 0xbe475251cf918ba7d9b99bd033a6a9373eba368908730b4b1a91ba28b1757fb0. Chain 2 (Bitcoin): anchored in block 960095 (2026-07-29T11:07:37Z), 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/HKI199229201.
Suite espanola No. 1, Op. 47 (arr. A. Segovia)*: Sevilla
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x7365aa84032a0eac28324316cc74a56e44856a914f1fde80d2dac989278d1d01. Chain 2 (Bitcoin): anchored in block 960327 (2026-07-31T00:26:26Z), 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/HKI199229202.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbf2993891e6216326d6c03d8395ec7a5bbf6e0db5848ccd7cefa55e63e0eed06. 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/HKI199229203.
12 Danzas espanolas (Spanish Dances), Op. 37 (arr. for guitar): Danza Espanola No. 5
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0b6e163f4cce364208f4adf72e502c9f346693071ab204bc10980af1ca701c9e. 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/HKI199229204.
Sonatina (excerpt): Andante From Sonatina
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x95584ee2fc8c674cacc8615d4b47d7711d73df331c4f4228ab1223592fa35bb8. 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/HKI199229205.
El sombrero de 3 picos (The 3-Cornered Hat) (arr. for guitar): Dance Of The Miller
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x390ab9121cd2310118e4e17439241ed0d7717be9796e671c6f414d9600c953c7. 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/HKI199229206.
24 Studies, Op. 31, "Lecons progressives": No. 19 in A Major
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x319a8f94419431a795ec35c1b57cd6fe0348571c61b2ff9399ef0a70cd238dbc. 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/HKI199229207.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbaeecc0a545a3219d0096876d73218417666314813c6d17b43387f0dc25a0620. 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/HKI199229208.
Souvenir de Russie, Op. 63: Fantasia, Op. 63, "Souvenir de Russie": Allegretto
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xd4f6f8195aae95c0abc22a1c2ebb80ffb9faa31cbbc2e80b3acb1bbbf25224d0. 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/HKI199229209.
6 Airs from the Magic Flute, Op. 19: No. 5. Konnte jeder brave Mann (Act I)
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x4d823313061fc7cfdfc63ecc4616dfc74433c1da8f7b42b9483618a9259b67b7. 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/HKI199229210.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfe66a95627513d8065270a76e9153a082f8f5fd66c1063ef4402b7e636438dee. 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/HKI199229211.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbb4ce8b778785082605c7e2ef33e477cb363cbdc56af1602b8ba32cfbaa2abd1. 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/HKI199229212.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x52c60845a1bd6c794a76703c5bf7eeb4ac44c0a0620a3aca7182aeb2afb2664e. Chain 2 (Bitcoin): anchored in block 960209 (2026-07-30T05:15:54Z), 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/HKI199229213.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5e37ab8a9d51b0448baee2e0776fd0920a1bb1c5f5a1c8bc5bbd3196ce604834. 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/HKI199229214.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x1048ade9c289de54fa03d5fa06e7314b75a6c92540bda713e4ce8d2ffde83bad. 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/HKI199229216.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x8c09aa64d4b74ddffd807c06a2f1f198fa3a37ebab954637a643de8b57988042. 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/HKI199229218.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xbbdcc703fcfb7f4300f94af54c3d05d85f4c85ece0030ffb2fd0ba3cc9cae371. 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/HKI199229220.
Regondi: 10 Etudes / Introduction and Caprice, Op. 23
Sor: Fantaisie, Op. 10 and 12 / Themes Et Menuets, Op. 11
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa3d7779be4ad60e9bd31298d5dff423caa834ef4628017ced5aa740e11907b7e. 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/HKI199649701.
Theme varies et 12 Minuets, Op. 11: Menuet No. 1
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x88abe573068731574c62ba26c3e1961bf4a751789e3014fe9e1d7d0ccf4fbf10. Chain 2 (Bitcoin): anchored in block 953515 (2026-06-13T12:53:06Z), 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/HKI199649704.
The Essentials: Classical Guitar, Vol. 1
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x28251be476c9893ad2846019fadf393a18f234e1ff5694d01ec878c72566ca97. Chain 2 (Bitcoin): anchored in block 956302 (2026-07-02T03:30:09Z), 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/USB8U1601608.
Sonatina canonica, Op. 196: II. Tempo di Siciliane
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x476fe41ea85e258e70a7c3fcff3acf75753b584887a279bde44f649c5195053d. Chain 2 (Bitcoin): anchored in block 960327 (2026-07-31T00:26:26Z), 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/USB8U1601616.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb3d192dba4ceacd323b8b8a07019164ec490546231424fb1a9c202eaa03f63e7. 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/USB8U1601645.
Flygande Grisen i Hämnden är ett klövdjur
Yannay: Music Now and from Almost Yesterday