4U or 4 U may refer to: Music 4U (album), by Elva Hsiao, 2002 4U (Christina Milian EP), 2015 4 U (Cody Simpson EP), 2010 4U: Outside, an EP by BtoB, 2021 "4U", a song by Aero Chord, 2015 "4U",
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0x41d0cda3293852bc70246c3c536efbba7f3ddf50062a0b7ee73aabf44f3a3f5d. 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/40e2e455-fa97-4755-bb26-869f7f324e9b.json and https://artists.proofprofile.net/proofs/artist/40e2e455-fa97-4755-bb26-869f7f324e9b.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).
Bitter Taste (From The Next Boy/Girl Band)
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xf402c4edf10d2492e50371cdae461744b4fec16754db8dd9211bb8639cf300c5. 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 via https://artists.proofprofile.net/api/v1/bot/ots/verify/track/NLZ291600122.
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xe93f1d1b97f3d61ce23ad9124dce06b993851730ad8c8cea6b34d4b897b409ad. Chain 2 (Bitcoin): anchored in block 958157 (2026-07-15T15:42:04Z), 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/NLZ291700263.