L13 or L-13 may refer to: Vehicles LET L-13 Blaník, a trainer glider , a Leninets-class submarine Stinson L-13, an American utility aircraft Zeppelin LZ 45, a German airship Proteins 60S ribo
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
Dual-chain trust anchor. Chain 1 (CopyrightChains): CopyrightID 0xfadc5e35345e4f98767b6cfc8fde3c1abe407984d1fd6ffeb095b9049ef8df4c. Chain 2 (Bitcoin): anchored in block 953626 (2026-06-14T11:41:45Z). Bridge: the canonical record inside this Bitcoin proof contains the same CopyrightID. Verify: download https://artists.proofprofile.net/proofs/artist/2761695e-5808-4e77-a967-161968194b2e.json and https://artists.proofprofile.net/proofs/artist/2761695e-5808-4e77-a967-161968194b2e.ots, run `ots verify -f record.json proof.ots` (https://opentimestamps.org).