Crate edx

ECDH key exchange using Ed25519 derived keys

use {
	ed25519_dalek::{SigningKey, SECRET_KEY_LENGTH},
	edx::{DeriveFactor, EdXchangeable, DERIVE_FACTOR_LENGTH},
};

let d_factor = DeriveFactor::from_bytes([42; DERIVE_FACTOR_LENGTH]);

let alice_sign = SigningKey::from_bytes(&[114; SECRET_KEY_LENGTH]);
let alice_verify = alice_sign.verifying_key();

let bob_sign = SigningKey::from_bytes(&[51; SECRET_KEY_LENGTH]);
let bob_verify = bob_sign.verifying_key();

let alice_kex_secret = alice_sign.edxchange(&bob_verify, &d_factor);
let bob_kex_secret = bob_sign.edxchange(&alice_verify, &d_factor);
assert_eq!(alice_kex_secret.as_bytes(), bob_kex_secret.as_bytes());

Structs

DeriveFactor

Derive factor used in key derivation. SHOULD be unique for each message. MUST NOT be all zero, otherwise it’s just the base key, and meaningless.

EdXPoint

Convenience wrapper for an EdwardsPoint, with From impls for key types in various libraries.

EdXScalar

Wrapper for a Scalar ensuring it’s clamped and reduced for the key exchange, with From impls for key types in various libraries.

SharedSecret

Result of a ECDH key exchange.

Constants

DERIVE_FACTOR_LENGTH

Traits

EdXchangeable

Trait for types holding secret scalar, which could be derived thus participate in key exchange.