Kontra
type: MusicGroup
description: A kontra (, 'three-stringed viola') is a Hungarian, Czech, Polish, Romanian, Slovak and Romani instrument common in Transylvania. Construction The kontra can be constructed new, but is most often a c
popularity: 4
followers: 5
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
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additional property: OTSHash
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additional property: OTSRecordURL
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additional property: OTSVerificationAPI
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additional property: OTSTimestamp
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  value: 2026-06-16T10:36:13Z
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 0x90d46cfe42e54456eedfb0570bfb0dc6a726bc865f1972945f210f5c0b562d9a. Chain 2 (Bitcoin): anchored in block 953997 (2026-06-16T20:07:57Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/1ec166dc-5693-48d0-ab1e-efaa619bf98a.json and https://artists.proofprofile.net/proofs/artist/1ec166dc-5693-48d0-ab1e-efaa619bf98a.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-16T20:07:57Z
album: Nitroglicerina EP
  type: MusicAlbum
  date published: 2012-04-30
  track: Nitroglicerina - DavidChristoph Remix
    type: MusicRecording
    duration: PT7M43S
    duration ms: 463701
    explicit: false
    by artist: Kontra
    in album: Nitroglicerina EP
      type: MusicAlbum
      date published: 2012-04-30
    isrc code: NLCK41014565
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    additional property: OTSVerificationAPI
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    additional property: OTSTimestamp
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    additional property: OTSVerifyInstructions
      type: PropertyValue
      value: 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
    subject of: OpenTimestamps Proof of Existence
      type: DigitalDocument
      encoding format: application/vnd.opentimestamps.ots
      description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xa837a3d80bd840e75a8cf9ceff1475374b12df5a4747b0af69cf10fafba8b52b. Chain 2 (Bitcoin): anchored in block 958601 (2026-07-18T19:27:02Z), 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/NLCK41014565.
      date published: 2026-07-18T19:27:02Z
    audio: Nitroglicerina - DavidChristoph Remix
      type: AudioObject
      additional property: Tempo (BPM)
        type: PropertyValue
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      additional property: Musical Key
        type: PropertyValue
        value: 4
      additional property: Mode (Major/Minor)
        type: PropertyValue
        value: 0
      additional property: Time Signature
        type: PropertyValue
        value: 4
      additional property: Danceability
        type: PropertyValue
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      additional property: Energy
        type: PropertyValue
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      additional property: Speechiness
        type: PropertyValue
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      additional property: Acousticness
        type: PropertyValue
        value: 0
      additional property: Instrumentalness
        type: PropertyValue
        value: 0.89
      additional property: Liveness
        type: PropertyValue
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      additional property: Valence (Positivity)
        type: PropertyValue
        value: 0.036
      additional property: Loudness (dB)
        type: PropertyValue
        value: -12.789
      additional property: Key Name
        type: PropertyValue
        value: E
      additional property: Mode Name
        type: PropertyValue
        value: Minor