Maarten van der Grinten
type: MusicGroup
popularity: 25
followers: 2205
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
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additional property: OTSHash
additional property: OTSBitcoinBlock
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additional property: OTSBitcoinBlockVerifyURL
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additional property: OTSProofURL
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  value: https://artists.proofprofile.net/proofs/artist/788ee004-6b8d-4488-aece-3d3c4876ac54.ots
additional property: OTSRecordURL
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  value: https://artists.proofprofile.net/proofs/artist/788ee004-6b8d-4488-aece-3d3c4876ac54.json
additional property: OTSVerificationAPI
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  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/artist/788ee004-6b8d-4488-aece-3d3c4876ac54
additional property: OTSTimestamp
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additional property: OTSCanonicalRecord
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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
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  description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x2b56d8e3e6c0f37ab46593cdb0314c25073e99041c0bb0ff067e2712eef587c8. 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/788ee004-6b8d-4488-aece-3d3c4876ac54.json and https://artists.proofprofile.net/proofs/artist/788ee004-6b8d-4488-aece-3d3c4876ac54.ots, the client at https://opentimestamps.org runs `ots verify -f record.json proof.ots`.
  date published: 2026-06-12T19:24:56Z
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album: Nine Stories from
  type: MusicAlbum
  date published: 2009-10-30
album: A Guitar, a Man & a Song, Vol. I
  type: MusicAlbum
  date published: 2023-01-06
album: 88
  type: MusicAlbum
  date published: 2023-01-20
album: Along Came Betty
  type: MusicAlbum
  date published: 2023-02-17
album: The End of a Love Affair
  type: MusicAlbum
  date published: 2023-03-03
album: A Guitar, a Man & a Song, Vol. II
  type: MusicAlbum
  date published: 2023-04-14
  track: Manhã de Carnaval
    type: MusicRecording
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    by artist: Maarten van der Grinten
    in album: A Guitar, a Man & a Song, Vol. II
      type: MusicAlbum
      date published: 2023-04-14
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    additional property: OTSVerificationAPI
      type: PropertyValue
      value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLP1U2300007
    additional property: OTSTimestamp
      type: PropertyValue
      value: 2026-07-21T03:51:22Z
    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 0x1de468b51e1a74a375eb2193168b26fe5c913de1c8396186ecff1d068bf25262. Chain 2 (Bitcoin): anchored in block 958959 (2026-07-21T03:51:22Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLP1U2300007 — a six-check JSON result.
      date published: 2026-07-21T03:51:22Z
    audio: Manhã de Carnaval
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      additional property: Tempo (BPM)
        type: PropertyValue
        value: 120.877
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      additional property: Danceability
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      additional property: Energy
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      additional property: Speechiness
        type: PropertyValue
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      additional property: Instrumentalness
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      additional property: Liveness
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      additional property: Valence (Positivity)
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      additional property: Loudness (dB)
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      additional property: Key Name
        type: PropertyValue
        value: D
      additional property: Mode Name
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album: You Don't Know What Love Is
  type: MusicAlbum
  date published: 2023-09-29
album: A Guitar, a Man & a Song, Vol. III
  type: MusicAlbum
  date published: 2024-01-26
  track: The End of the World
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    duration: PT2M53S
    duration ms: 173322
    explicit: false
    by artist: Maarten van der Grinten
    in album: A Guitar, a Man & a Song, Vol. III
      type: MusicAlbum
      date published: 2024-01-26
    isrc code: NLP1U2400004
    additional property: CopyrightID
    additional property: CopyrightStatus
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      value: registered
    additional property: CopyrightRegisteredAt
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      value: 2026-07-03T22:23:17+00:00
    additional property: CopyrightChainExplorerURL
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    additional property: OTSVerificationAPI
      type: PropertyValue
      value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLP1U2400004
    additional property: OTSTimestamp
      type: PropertyValue
      value: 2026-07-04T10:04:33Z
    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 0x6a561ef9adac85d2f17d83cbf04dba63798cf05c6bd14b21f0c657bade2d851a. Chain 2 (Bitcoin): anchored in block 956634 (2026-07-04T10:04:33Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLP1U2400004 — a six-check JSON result.
      date published: 2026-07-04T10:04:33Z
    audio: The End of the World
      type: AudioObject
      additional property: Tempo (BPM)
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        value: 105.613
      additional property: Musical Key
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      additional property: Mode (Major/Minor)
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      additional property: Time Signature
        type: PropertyValue
        value: 4
      additional property: Danceability
        type: PropertyValue
        value: 0.448
      additional property: Energy
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      additional property: Acousticness
      additional property: Instrumentalness
      additional property: Liveness
      additional property: Valence (Positivity)
      additional property: Loudness (dB)
      additional property: Key Name
      additional property: Mode Name
  track: You Don’t Know What Love Is (alternate take)
album: Have Yourself a Merry Little Christmas
album: A Baritone Christmas
album: Vincent (Starry Starry Night)
track: An den Kleinen Radioapparat (a.k.a The Secret Mariage)

Energy
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value: 0.133

Speechiness
type: PropertyValue
value: 0.042

Acousticness
type: PropertyValue
value: 0.962

Instrumentalness
type: PropertyValue
value: 0.942

Liveness
type: PropertyValue
value: 0.134

Valence (Positivity)
type: PropertyValue
value: 0.319

Loudness (dB)
type: PropertyValue
value: -17.631

Key Name
type: PropertyValue
value: A

Mode Name
type: PropertyValue
value: Major

You Don’t Know What Love Is (alternate take)
type: MusicRecording
duration: PT4M57S
duration ms: 297317
explicit: false
by artist: Maarten van der Grinten
in album: A Guitar, a Man & a Song, Vol. III
  type: MusicAlbum
  date published: 2024-01-26
isrc code: NLP1U2400005
additional property: CopyrightID
additional property: CopyrightStatus
  type: PropertyValue
  value: registered
additional property: CopyrightRegisteredAt
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  value: 2026-07-05T10:27:34+00:00
additional property: CopyrightChainExplorerURL
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  value: https://explorer.copyrightchains.com/tx/0x9785cde5b60c83128d6f7a7d31f0480794424893493b38c2b683cfd8dc3653b5
additional property: OTSHash
additional property: OTSBitcoinBlock
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additional property: OTSBitcoinBlockVerifyURL
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additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLP1U2400005
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-07-05T18:48:28Z
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 0x9785cde5b60c83128d6f7a7d31f0480794424893493b38c2b683cfd8dc3653b5. Chain 2 (Bitcoin): anchored in block 956822 (2026-07-05T18:48:28Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLP1U2400005 — a six-check JSON result.
  date published: 2026-07-05T18:48:28Z
audio: You Don’t Know What Love Is (alternate take)
  type: AudioObject
  additional property: Tempo (BPM)
    type: PropertyValue
    value: 132.018
  additional property: Musical Key
    type: PropertyValue
    value: 5
  additional property: Mode (Major/Minor)
    type: PropertyValue
    value: 0
  additional property: Time Signature
    type: PropertyValue
    value: 4
  additional property: Danceability
    type: PropertyValue
    value: 0.586
  additional property: Energy
    type: PropertyValue
    value: 0.102
  additional property: Speechiness
    type: PropertyValue
    value: 0.064
  additional property: Acousticness
    type: PropertyValue
    value: 0.992
  additional property: Instrumentalness
    type: PropertyValue
    value: 0.921
  additional property: Liveness
    type: PropertyValue
    value: 0.115
  additional property: Valence (Positivity)
    type: PropertyValue
    value: 0.131
  additional property: Loudness (dB)
    type: PropertyValue
    value: -14.923
  additional property: Key Name
    type: PropertyValue
    value: F
  additional property: Mode Name
    type: PropertyValue
    value: Minor

Have Yourself a Merry Little Christmas
type: MusicAlbum
date published: 2024-12-06

A Baritone Christmas
type: MusicAlbum
date published: 2024-12-13

Vincent (Starry Starry Night)
type: MusicAlbum
date published: 2025-01-17

An den Kleinen Radioapparat (a.k.a The Secret Mariage)
type: MusicRecording
duration: PT1M32S
duration ms: 92133
explicit: false
by artist: Benjamin Herman
by artist: Maarten van der Grinten
in album: The Van der Grinten/Herman Quartet: Psychodixie for C-Melody Saxophone
  type: MusicAlbum
  date published: 1994
genre: dutch-jazz
isrc code: USLZJ1670434
additional property: CopyrightID
additional property: CopyrightStatus
  type: PropertyValue
  value: registered
additional property: CopyrightRegisteredAt
  type: PropertyValue
  value: 2026-07-30T14:37:58+00:00
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0xa609b642a9382e7cc6939a51ca88c83bfc09254913608a5ad9ae2e0a2cbea003
additional property: OTSHash
additional property: OTSBitcoinBlock
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additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/960268
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USLZJ1670434
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-07-30T14:53:07Z
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 0xa609b642a9382e7cc6939a51ca88c83bfc09254913608a5ad9ae2e0a2cbea003. Chain 2 (Bitcoin): anchored in block 960268 (2026-07-30T14:53:07Z), 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 at https://artists.proofprofile.net/api/v1/bot/ots/verify/track/USLZJ1670434 — a six-check JSON result.
  date published: 2026-07-30T14:53:07Z
audio: An den Kleinen Radioapparat (a.k.a The Secret Mariage)
  type: AudioObject
  additional property: Tempo (BPM)
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    value: 126.388
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    type: PropertyValue
    value: 2
  additional property: Mode (Major/Minor)
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    value: 1
  additional property: Time Signature
    type: PropertyValue
    value: 5
  additional property: Danceability
    type: PropertyValue
    value: 0.318
  additional property: Energy
    type: PropertyValue
    value: 0.296
  additional property: Speechiness
    type: PropertyValue
    value: 0.058
  additional property: Acousticness
    type: PropertyValue
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  additional property: Instrumentalness
    type: PropertyValue
    value: 0.485
  additional property: Liveness
    type: PropertyValue
    value: 0.285
  additional property: Valence (Positivity)
    type: PropertyValue
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  additional property: Loudness (dB)
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  additional property: Key Name
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  additional property: Mode Name
    type: PropertyValue
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