Vicente Calderón Pérez-Cavada (; 27 May 1913 – 24 March 1987) was a Spanish businessman and president of Atlético Madrid for 20 years. As President of Atlético Madrid he helped in getting their new
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 0x05d1662491352d6453e6b965b86d8ba628cd6c87f8b19cd75522f8c526f95fdc. 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/f92168e2-b1e9-4c01-b3d3-efabe1fea938.json and https://artists.proofprofile.net/proofs/artist/f92168e2-b1e9-4c01-b3d3-efabe1fea938.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 0x6b7602b37b1c43b1ffe7395c17e0192ccf4b1b12c03fe02358f03916f4fc914d. Chain 2 (Bitcoin): anchored in block 956578 (2026-07-04T02:23:20Z), 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/ES6062408101.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb44d901450f7fe552c0d89f739340bfd6c79fb26ec5fa0732761c6bbb9749a5b. Chain 2 (Bitcoin): anchored in block 956639 (2026-07-04T11:19:20Z), 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/ES6062421301.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xed4a4c84c60b2ccadbbf4c44144e4c0f984d676f94d1a6e1cfd795ef800b939a. 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/ES6062524702.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x77ce8fddf053dc2c40a1df2b83c55db3740923e0aa512d9788a4f8c19c735ddc. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/ES6062524701.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xdac01a24767d9bfaea8a78eb9619755826697dd34d333fd421bc284c3100de58. 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/ES6062412101.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0bb077fdf2be8ff9fb2d3762662a292b8765175fa6c3b2523b91b63361b420b6. 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/ES6062416001.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfb39037b217fd4cf19bfe674d84b82006fc16b4c974d8ce4bde4f9d916840a57. Chain 2 (Bitcoin): anchored in block 953520 (2026-06-13T13:32:09Z), 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/ES6062421101.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xb482415c61dc0126c8d58b0d7ef06ffce0df1c90179799087353ded3c0739edf. 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/ES6062524706.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x9597835885a2852f70717cfe0bd0806937a9412177628a0a852efa291cffaed4. 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/ES6062418701.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa3583557297478ad215f45e84e81b695417eca319e9ff9fc44b08c37c5de5a68. 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/ES6062592408.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x90a961dd49d070966b838dd1cf1b8d5bafead34c87990c36900c5d24efc64920. 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/ES6062415001.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x72c1df7db1b556c986be27f8f109de4205dc10ba9d403eda0e1c6cc75a51f966. 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/ES6062524710.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x947e88807e898a37ed65de4749b71e93e0d6b4fabe2c593a848c66bd95f0d76c. 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/ES6062531101.