Ed25519 signature
The deterministic 64-byte elliptic-curve signature scheme Truestamp uses to sign the 32-byte domain-separated SHA-256 hashes of items, blocks, entropy observations, and proof bundle payloads, proving Truestamp's signing key endorsed exactly that object.
Overview
An Ed25519 signature is a 64-byte digital signature made with Truestamp’s Ed25519 signing key over a 32-byte domain-separated SHA-256 hash, never over raw user data. Truestamp signs item hashes, block hashes, entropy observation hashes, and the fixed-width signing payload of every proof bundle. A valid signature, checked against Truestamp’s public key, proves that key endorsed exactly that fingerprint and that the object has not been altered since; it does not by itself prove when the data was submitted. Ed25519 is deterministic (the same key and message always produce the same signature), fast to make and check, and small enough to embed in every record and bundle. See Ed25519 signatures for the full treatment and the proof bundle wire format for the signed payload layout.
- Cryptographic Accelerators for Digital Signature Based on Ed25519
- Difference between X25519 and Ed25519 - Cryptography Stack Exchange
- Ed25519 Deep Dive Addendum (r/crypto)
- Ed25519: high-speed high-security signatures
- EdDSA (Wikipedia)
- Item hash
- RFC 8032: Edwards-Curve Digital Signature Algorithm (EdDSA)
- ssh-keygen: Wikipedia
- The Provable Security of Ed25519: Theory and Practice