Jan Krejča
type: MusicGroup
genre: chamber music
popularity: 3
followers: 8
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0xc62400a004ff59fcc49c3a23b3421f842b521510db577941189c086ec281b6dc
additional property: OTSHash
additional property: OTSBitcoinBlock
  type: PropertyValue
  value: 954066
additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/954066
additional property: OTSProofURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/6915b69e-f763-4d90-a882-1fe7e381923f.ots
additional property: OTSRecordURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/6915b69e-f763-4d90-a882-1fe7e381923f.json
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/artist/6915b69e-f763-4d90-a882-1fe7e381923f
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-06-17T08:11:48Z
additional property: OTSCanonicalRecord
  type: PropertyValue
  value: {"copyright_id":"0xc62400a004ff59fcc49c3a23b3421f842b521510db577941189c086ec281b6dc","name":"Jan Krejča","registered_at":"2026-06-17T02:36:04Z","symbol":"NIM1254292","token_address":"0x437ca82ac320ae0d98ffdf6436c618e7bccedef3","type":"artist","uuid":"6915b69e-f763-4d90-a882-1fe7e381923f"}
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 0xc62400a004ff59fcc49c3a23b3421f842b521510db577941189c086ec281b6dc. 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/6915b69e-f763-4d90-a882-1fe7e381923f.json and https://artists.proofprofile.net/proofs/artist/6915b69e-f763-4d90-a882-1fe7e381923f.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-17T08:11:48Z
  text: {"copyright_id":"0xc62400a004ff59fcc49c3a23b3421f842b521510db577941189c086ec281b6dc","name":"Jan Krejča","registered_at":"2026-06-17T02:36:04Z","symbol":"NIM1254292","token_address":"0x437ca82ac320ae0d98ffdf6436c618e7bccedef3","type":"artist","uuid":"6915b69e-f763-4d90-a882-1fe7e381923f"}
track: Letní ukolébavka
  type: MusicRecording
  duration: PT2M15S
  duration ms: 135253
  explicit: false
  by artist: Pavel Jurkovič
  by artist: Hana Blažíková
  by artist: Jan Krejča
  in album: Jurkovič: Ukolébavky
    type: MusicAlbum
    date published: 2018-05-04
  isrc code: CZA161800383
  additional property: CopyrightID
  additional property: CopyrightStatus
    type: PropertyValue
    value: registered
  additional property: CopyrightRegisteredAt
    type: PropertyValue
    value: 2026-06-27T07:28:24+00:00
  additional property: CopyrightChainExplorerURL
    type: PropertyValue
    value: https://explorer.copyrightchains.com/tx/0xd1f09a418840729b611fd38546b4ec4c6ca4f880f7b0f086412d8597ff499222
  additional property: OTSHash
  additional property: OTSBitcoinBlock
    type: PropertyValue
    value: 956304
  additional property: OTSBitcoinBlockVerifyURL
    type: PropertyValue
    value: https://blockstream.info/api/block-height/956304
  additional property: OTSVerificationAPI
    type: PropertyValue
    value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/CZA161800383
  additional property: OTSTimestamp
    type: PropertyValue
    value: 2026-07-02T03:55:08Z
  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 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 0xd1f09a418840729b611fd38546b4ec4c6ca4f880f7b0f086412d8597ff499222. 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/CZA161800383.
    date published: 2026-07-02T03:55:08Z
  audio: Letní ukolébavka
    type: AudioObject
    additional property: Tempo (BPM)
      type: PropertyValue
      value: 105.063
    additional property: Musical Key
      type: PropertyValue
      value: 0
    additional property: Mode (Major/Minor)
      type: PropertyValue
      value: 1
    additional property: Time Signature
      type: PropertyValue
      value: 4
    additional property: Danceability
      type: PropertyValue
      value: 0.358
    additional property: Energy
      type: PropertyValue
      value: 0.012
    additional property: Speechiness
      type: PropertyValue
      value: 0.047
    additional property: Acousticness
      type: PropertyValue
      value: 0.992
    additional property: Instrumentalness
      type: PropertyValue
      value: 0
    additional property: Liveness
      type: PropertyValue
      value: 0.137
    additional property: Valence (Positivity)
      type: PropertyValue
      value: 0.151
    additional property: Loudness (dB)
      type: PropertyValue
      value: -30.755
    additional property: Key Name
      type: PropertyValue
      value: C
    additional property: Mode Name
      type: PropertyValue
      value: Major
track: Pro Tetuu Kapraňovou
  type: MusicRecording
  duration: PT2M15S
  duration ms: 135786
  explicit: false
  by artist: Pavel Jurkovič
  by artist: Hana Blažíková
  by artist: Martina Bernášková
  by artist: Kateřina Ghannudi
  by artist: Jan Krejča
  by artist: Martin Rudovský
  in album: Jurkovič: Ukolébavky
    type: MusicAlbum
    date published: 2018-05-04
  isrc code: CZA161800402
  additional property: CopyrightID
  additional property: CopyrightStatus
    type: PropertyValue
    value: registered
  additional property: CopyrightRegisteredAt
    type: PropertyValue
    value: 2026-07-22T11:53:44+00:00
  additional property: CopyrightChainExplorerURL
    type: PropertyValue
    value: https://explorer.copyrightchains.com/tx/0x193a3f38d79fab3c08281dec81d8a24ac5c33d053665a1082ae52e4cd89525bc
  additional property: OTSHash
  additional property: OTSBitcoinBlock
    type: PropertyValue
    value: 959128
  additional property: OTSBitcoinBlockVerifyURL
    type: PropertyValue
    value: https://blockstream.info/api/block-height/959128
  additional property: OTSVerificationAPI
    type: PropertyValue
    value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/CZA161800402
  additional property: OTSTimestamp
    type: PropertyValue
    value: 2026-07-22T12:33:25Z
  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 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 0x193a3f38d79fab3c08281dec81d8a24ac5c33d053665a1082ae52e4cd89525bc. Chain 2 (Bitcoin): anchored in block 959128 (2026-07-22T12:33:25Z), 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/CZA161800402.
    date published: 2026-07-22T12:33:25Z
  audio: Pro Tetuu Kapraňovou
    type: AudioObject
    additional property: Tempo (BPM)
      type: PropertyValue
      value: 96.451
    additional property: Musical Key
      type: PropertyValue
      value: 7
    additional property: Mode (Major/Minor)
      type: PropertyValue
      value: 1
    additional property: Time Signature
      type: PropertyValue
      value: 5
    additional property: Danceability
      type: PropertyValue
      value: 0.362
    additional property: Energy
      type: PropertyValue
      value: 0.039
    additional property: Speechiness
      type: PropertyValue
      value: 0.039
    additional property: Acousticness
      type: PropertyValue
      value: 0.951
    additional property: Instrumentalness
      type: PropertyValue
      value: 0.002
    additional property: Liveness
      type: PropertyValue
      value: 0.053
    additional property: Valence (Positivity)
    additional property: Loudness (dB)
    additional property: Key Name
    additional property: Mode Name

Valence (Positivity)
type: PropertyValue
value: 0.321

Loudness (dB)
type: PropertyValue
value: -25.508

Key Name
type: PropertyValue
value: G

Mode Name
type: PropertyValue
value: Major