Sjef
type: MusicGroup
description: Sjef is a given name. Notable people with the given name include: Sjef Hensgens (1948–2024), Dutch middle-distance runner Sjef Janssen (born 1950), Dutch dressage coach Sjef Mertens (1926–2004), Dut
popularity: 2
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0x07f6e3b1807f04ce20e5d7f3cad07b198507a1ab5694415e6c2e2bce09f8578b
additional property: OTSHash
additional property: OTSBitcoinBlock
  type: PropertyValue
  value: 954689
additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/954689
additional property: OTSProofURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/e3091f27-6703-4c30-93ad-be1215f451a1.ots
additional property: OTSRecordURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/e3091f27-6703-4c30-93ad-be1215f451a1.json
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/artist/e3091f27-6703-4c30-93ad-be1215f451a1
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-06-21T10:35:31Z
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
subject of: OpenTimestamps Proof of Existence
  type: DigitalDocument
  encoding format: application/vnd.opentimestamps.ots
  description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x07f6e3b1807f04ce20e5d7f3cad07b198507a1ab5694415e6c2e2bce09f8578b. Chain 2 (Bitcoin): anchored in block 954689 (2026-06-21T10:35:31Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/e3091f27-6703-4c30-93ad-be1215f451a1.json and https://artists.proofprofile.net/proofs/artist/e3091f27-6703-4c30-93ad-be1215f451a1.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-21T10:35:31Z
album: The Void Digital Series: V.D.009 Sjef ep
  type: MusicAlbum
  date published: 2023-06-01