U3
type: MusicGroup
description: U3 or U-3 may refer to: Transportation U3, an underground rapid transit line in many major German/Austrian cities: U3 (Berlin U-Bahn) U3 (Frankfurt U-Bahn) U3 (Hamburg U-Bahn) U3 (Munich U-Bahn)
popularity: 9
followers: 564
additional property: CopyrightID
additional property: CopyrightChainExplorerURL
  type: PropertyValue
  value: https://explorer.copyrightchains.com/tx/0x11ea4bc5ef1082ec19320361d0e6097b0fc02f6c63104dc609042637737412a9
additional property: OTSHash
additional property: OTSBitcoinBlock
  type: PropertyValue
  value: 954784
additional property: OTSBitcoinBlockVerifyURL
  type: PropertyValue
  value: https://blockstream.info/api/block-height/954784
additional property: OTSProofURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/f14689fc-4549-47b0-94fd-477b691562bd.ots
additional property: OTSRecordURL
  type: PropertyValue
  value: https://artists.proofprofile.net/proofs/artist/f14689fc-4549-47b0-94fd-477b691562bd.json
additional property: OTSVerificationAPI
  type: PropertyValue
  value: https://artists.proofprofile.net/api/v1/bot/ots/verify/artist/f14689fc-4549-47b0-94fd-477b691562bd
additional property: OTSTimestamp
  type: PropertyValue
  value: 2026-06-22T02:53:59Z
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 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 0x11ea4bc5ef1082ec19320361d0e6097b0fc02f6c63104dc609042637737412a9. Chain 2 (Bitcoin): anchored in block 954784 (2026-06-22T02:53:59Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/f14689fc-4549-47b0-94fd-477b691562bd.json and https://artists.proofprofile.net/proofs/artist/f14689fc-4549-47b0-94fd-477b691562bd.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
  date published: 2026-06-22T02:53:59Z
album: In Waves
  type: MusicAlbum
  date published: 2020-08-28
album: Christmas Time Is Here
  type: MusicAlbum
  date published: 2020-12-01