A compact Ed25519 and X25519 implementation for Rust
- Formally-verified Curve25519 field arithmetic
no_std
-friendly- WebAssembly-friendly
- Compute@Edge-friendly
- Lightweight
- Zero dependencies if randomness is provided by the application
- Only one portable dependency (
getrandom
) if not - Supports incremental signatures (streaming API)
- Safe and simple Rust interface
API documentation
Example usage
cargo.toml
:
[dependencies]
ed25519-compact = "2"
Example code:
// A message to sign and verify.
let message = b"test";
// Generates a new key pair using a random seed.
// A given seed will always produce the same key pair.
let key_pair = KeyPair::from_seed(Seed::default());
// Computes a signature for this message using the secret part of the key pair.
let signature = key_pair.sk.sign(message, Some(Noise::default()));
// Verifies the signature using the public part of the key pair.
key_pair
.pk
.verify(message, &signature)
.expect("Signature didn't verify");
// Verification of a different message using the same signature and public key fails.
key_pair
.pk
.verify(b"A different message", &signature)
.expect_err("Signature shouldn't verify");
// All these structures can be viewed as raw bytes simply by dereferencing them:
let signature_as_bytes: &[u8] = signature.as_ref();
println!("Signature as bytes: {:?}", signature_as_bytes);
Incremental API example usage
Messages can also be supplied as multiple parts (streaming API) in order to handle large messages without using much memory:
/// Creates a new key pair.
let kp = KeyPair::generate();
/// Creates a state for an incremental signer.
let mut st = kp.sk.sign_incremental(Noise::default());
/// Feeds the message as any number of chunks, and sign the concatenation.
st.absorb("mes");
st.absorb("sage");
let signature = st.sign();
/// Creates a state for an incremental verifier.
let mut st = kp.pk.verify_incremental(&signature)?;
/// Feeds the message as any number of chunks, and verify the concatenation.
st.absorb("mess");
st.absorb("age");
st.verify()?;
Cargo features
self-verify
: after having computed a new signature, verify that is it valid. This is slower, but improves resilience against fault attacks. It is enabled by default on WebAssembly targets.std
: disablesno_std
compatibility in order to make errors implement the standardError
trait.random
(enabled by default): addsDefault
implementations to theSeed
andNoise
objects, in order to securely create random keys and noise.traits
: add support for the traits from theed25519
andsignature
crates.pem
: add support for importing/exporting keys as OpenSSL-compatible PEM files.blind-keys
: add support for key blinding.opt_size
: Enable size optimizations (based on benchmarks, 8-15% size reduction at the cost of 6.5-7% performance).x25519
: Enable support for the X25519 key exchange system.disable-signatures
: Disable support for signatures, and only compile support for X25519.