David Pavelka (born 18 May 1991) is a Czech former professional footballer who last played as a midfielder for Sparta Prague B and the Czech Republic national team. Club career First spell at Sparta
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 0x3ce2b600e9d33fbad8274024596a8404c8cbdeedc2134c5e6611cbd9fda255b5. Chain 2 (Bitcoin): anchored in block 954066 (2026-06-17T08:11:48Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/57eed7e2-1ffa-4443-8729-f8935da59a51.json and https://artists.proofprofile.net/proofs/artist/57eed7e2-1ffa-4443-8729-f8935da59a51.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Cuatro Estaciones Porteñas: Otoño Porteño
Cuatrocientas Estaciones de Ástor Piazzolla
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 0x4006b7b707b80f165faa19c4432911de5ca779566aeae1d1ed708ff5b496195d. Chain 2 (Bitcoin): anchored in block 960468 (2026-07-31T21:25:57Z), 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/CZB872101001.
Cuatro Estaciones Porteñas: Invierno Porteño
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xcd685bf14abb03608799b19e8550e89166c838a20ec8c5db4d06a7336a44bf99. Chain 2 (Bitcoin): anchored in block 960337 (2026-07-31T02:51:48Z), 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/CZB872101002.
Cuatro Estaciones Porteñas: Primavera Porteña
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xec1f18e7b65a22a65ae45a840b17ae4062ef42f0d7816ad429ddfb44e1ddaa19. Chain 2 (Bitcoin): anchored in block 960354 (2026-07-31T05:48:18Z), 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/CZB872101003.
Cuatro Estaciones Porteñas: Verano Porteño
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x5d5ce0b4882c309cfeaab047a84cab9abfcc92e82752a0ec1d2b96d6b85f7cfb. 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/CZB872101004.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0a403390669d99478bd7e27b0fe4537e4af21490fcf95fdbbf11497aea750b35. 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/CZB872101005.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf8bcd943dc3d6f1bb1804a58d44ec79485a82d4c5fb6d4b4ec53e673780b32e0. Chain 2 (Bitcoin): anchored in block 960500 (2026-08-01T03:13:03Z), 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/CZB872101007.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x6ff5fe1ef38a5023d1b658e92fdcbcd0a5a693bf28de4801bfe7b109a547fe5a. 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/CZB872101008.