SFERA
type: MusicGroup
description: SFera is a science fiction society from Zagreb, Croatia. It was founded in 1976, thus marking the beginnings of organized science fiction fandom in the region. SFera is the official organizer of SFe
popularity: 12
followers: 45
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0x6ace4abaab3dd64be485f2772c8bf9e07c2d4f3afbbc29bb87ef699c1e939a86
additional property: OTSHash
additional property: OTSBitcoinBlock
  type: PropertyValue
  value: 953648
additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/953648
additional property: OTSProofURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/43ffa22c-9ad5-4c9b-840b-530c6e7ab704.ots
additional property: OTSRecordURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/43ffa22c-9ad5-4c9b-840b-530c6e7ab704.json
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/artist/43ffa22c-9ad5-4c9b-840b-530c6e7ab704
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-06-14T15:20:52Z
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 0x6ace4abaab3dd64be485f2772c8bf9e07c2d4f3afbbc29bb87ef699c1e939a86. Chain 2 (Bitcoin): anchored in block 953648 (2026-06-14T15:20:52Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/43ffa22c-9ad5-4c9b-840b-530c6e7ab704.json and https://artists.proofprofile.net/proofs/artist/43ffa22c-9ad5-4c9b-840b-530c6e7ab704.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-14T15:20:52Z
album: SFERA BRAKU GRAWITACJI
  type: MusicAlbum
  date published: 2025-04-17
  track: SFERA BRAKU GRAWITACJI

SFERA BRAKU GRAWITACJI
type: MusicRecording
duration: PT2M43S
duration ms: 163999
explicit: true
by artist: SFERA
in album: SFERA BRAKU GRAWITACJI
  type: MusicAlbum
  date published: 2025-04-17
isrc code: PL90S2500037
additional property: CopyrightID
additional property: CopyrightStatus
  type: PropertyValue
  value: registered
additional property: CopyrightRegisteredAt
  type: PropertyValue
  value: 2026-06-08T09:38:09+00:00
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0x0c6453703894cc62323c0b537f3680a424e01754fad0aebcc7ebb4928cca16dd
additional property: OTSHash
additional property: OTSBitcoinBlock
  type: PropertyValue
  value: 953520
additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/953520
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/track/PL90S2500037
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-06-13T13:32:09+00:00
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
additional property: ProofProfileEvidenceStatus
  type: PropertyValue
  value: verified-cc-db-prod
additional property: TokenDeploymentConfirmed
  type: PropertyValue
  value: true
additional property: ContentHash
additional property: BitcoinBlock
  type: PropertyValue
  value: 953520
additional property: BitcoinTime
  type: PropertyValue
  value: 2026-06-13T13:32:09+00:00
subject of: OpenTimestamps Proof of Existence
  type: DigitalDocument
  encoding format: application/vnd.opentimestamps.ots
  description: Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x0c6453703894cc62323c0b537f3680a424e01754fad0aebcc7ebb4928cca16dd. Chain 2 (Bitcoin): anchored in block 953528 (2026-06-13T15:41:10Z), 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/PL90S2500037.
  date published: 2026-06-13T15:41:10Z
audio: SFERA BRAKU GRAWITACJI
  type: AudioObject
  additional property: Tempo (BPM)
    type: PropertyValue
    value: 131.594
  additional property: Musical Key
    type: PropertyValue
    value: 9
  additional property: Mode (Major/Minor)
    type: PropertyValue
    value: 1
  additional property: Time Signature
    type: PropertyValue
    value: 6
  additional property: Danceability
    type: PropertyValue
    value: 0.824
  additional property: Energy
    type: PropertyValue
    value: 0.691
  additional property: Speechiness
    type: PropertyValue
    value: 0.345
  additional property: Acousticness
    type: PropertyValue
    value: 0.447
  additional property: Instrumentalness
    type: PropertyValue
    value: 0.753
  additional property: Liveness
    type: PropertyValue
    value: 0.144
  additional property: Valence (Positivity)
    type: PropertyValue
    value: 0.734
  additional property: Loudness (dB)
    type: PropertyValue
    value: -11.467
  additional property: Key Name
    type: PropertyValue
    value: A
  additional property: Mode Name
    type: PropertyValue
    value: Major