EX-3
type: MusicGroup
description: EX-3 was a Spanish mákina group composed of David Amo, Alex Castellano, and Julio Navas. They are known for being one of the most representative groups of the 90's Spanish "Mákina" phenomenon, at the
popularity: 7
followers: 123
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0xa9ed9a4751e46ee02bbbda078eeb016ee84cf1559e546e139cd83752c506ab98
additional property: OTSHash
additional property: OTSBitcoinBlock
  type: PropertyValue
  value: 954647
additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/954647
additional property: OTSProofURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/d7ad3862-1f48-40e8-9223-7e114b99a19a.ots
additional property: OTSRecordURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/d7ad3862-1f48-40e8-9223-7e114b99a19a.json
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/artist/d7ad3862-1f48-40e8-9223-7e114b99a19a
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-06-21T04:36:58Z
additional property: OTSCanonicalRecord
additional property: OTSVerifyInstructions
  type: PropertyValue
  value: 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
subject of: OpenTimestamps Proof of Existence
  type: DigitalDocument
  encoding format: application/vnd.opentimestamps.ots
  description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa9ed9a4751e46ee02bbbda078eeb016ee84cf1559e546e139cd83752c506ab98. Chain 2 (Bitcoin): anchored in block 954647 (2026-06-21T04:36:58Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/d7ad3862-1f48-40e8-9223-7e114b99a19a.json and https://artists.proofprofile.net/proofs/artist/d7ad3862-1f48-40e8-9223-7e114b99a19a.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-21T04:36:58Z
album: Estres
  type: MusicAlbum
  date published: 2021-03-26