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Remove SignalKeyPair, rename all instances of SignalKeyPair to X25519KeyPair, pass all tests.

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This commit is contained in:
François Garillot
2020-06-13 09:07:55 -04:00
parent e9add9fd7a
commit e9fa474c58
3 changed files with 23 additions and 153 deletions
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src/keypair.rs
-130
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@@ -219,93 +219,9 @@ impl KeyPair for X25519KeyPair {
}
}
/// A custom, minimalistic Key pair struct built on Key, aimed at reproducing the behavior of libsignal's keypairs
#[derive(Debug, PartialEq, Eq)]
pub struct SignalKeyPair {
pk: Key,
sk: Key,
}
impl SignalKeyPair {
fn clamp_scalar(mut scalar: [u8; 32]) -> ::curve25519_dalek::scalar::Scalar {
scalar[0] &= 248;
scalar[31] &= 127;
scalar[31] |= 64;
::curve25519_dalek::scalar::Scalar::from_bits(scalar)
}
fn gen<R: RngCore + CryptoRng>(rng: &mut R) -> (Vec<u8>, Vec<u8>) {
let mut bits = [0u8; 32];
rng.fill_bytes(&mut bits);
// It's proper to sanitize the scalar here, and reproduces x25519::StaticSecret::new
let sk = SignalKeyPair::clamp_scalar(bits);
let pk = ::curve25519_dalek::constants::X25519_BASEPOINT * sk;
(pk.as_bytes().to_vec(), sk.as_bytes().to_vec())
}
}
impl KeyPair for SignalKeyPair {
type Repr = Key;
fn public(&self) -> &Self::Repr {
&self.pk
}
fn private(&self) -> &Self::Repr {
&self.sk
}
fn new(public: Self::Repr, private: Self::Repr) -> Result<Self, InternalPakeError> {
Ok(SignalKeyPair {
pk: public,
sk: private,
})
}
fn generate_random<R: RngCore + CryptoRng>(rng: &mut R) -> Result<Self, InternalPakeError> {
let (public, private) = SignalKeyPair::gen(rng);
Ok(SignalKeyPair {
pk: Key(public),
sk: Key(private),
})
}
fn public_from_private(secret: &Self::Repr) -> Self::Repr {
let mut secret_data = [0u8; 32];
secret_data.copy_from_slice(&secret.0[..]);
let base_data = ::x25519_dalek::X25519_BASEPOINT_BYTES;
Key(::x25519_dalek::x25519(secret_data, base_data).to_vec())
}
fn check_public_key(key: Self::Repr) -> Result<Self::Repr, InternalPakeError> {
let mut key_bytes = [0u8; 32];
key_bytes.copy_from_slice(&key);
let point = ::curve25519_dalek::montgomery::MontgomeryPoint(key_bytes)
.to_edwards(1)
.ok_or(InternalPakeError::PointError)?;
if !point.is_torsion_free() {
Err(InternalPakeError::SubGroupError)
} else {
Ok(key)
}
}
fn diffie_hellman(pk: Self::Repr, sk: Self::Repr) -> Vec<u8> {
let mut pk_data = [0; 32];
pk_data.copy_from_slice(&pk.0[..]);
let mut sk_data = [0; 32];
sk_data.copy_from_slice(&sk.0[..]);
::x25519_dalek::x25519(sk_data, pk_data).to_vec()
}
}
#[cfg(test)]
mod tests {
use super::*;
use proptest::prelude::*;
proptest! {
#[test]
@@ -321,51 +237,5 @@ mod tests {
prop_assert_eq!(&X25519KeyPair::public_from_private(sk), pk);
}
#[test]
fn test_signal_check(kp in SignalKeyPair::uniform_keypair_strategy()) {
let pk = kp.public();
prop_assert!(SignalKeyPair::check_public_key(pk.clone()).is_ok());
}
#[test]
fn test_signal_pub_from_priv(kp in SignalKeyPair::uniform_keypair_strategy()) {
let pk = kp.public();
let sk = kp.private();
prop_assert_eq!(&SignalKeyPair::public_from_private(sk), pk);
}
#[test]
fn test_signal_x25519_roundtrips(kp_signal in SignalKeyPair::uniform_keypair_strategy(),
kp_x25519 in X25519KeyPair::uniform_keypair_strategy()) {
let kp_signal_bytes: &[u8] = &kp_signal.to_arr();
let kp_x25519_bytes: &[u8] = &kp_x25519.to_arr();
let reinterpret_signal = X25519KeyPair::from_bytes(kp_signal_bytes).unwrap();
let reinterpret_x25519 = SignalKeyPair::from_bytes(kp_x25519_bytes).unwrap();
prop_assert_eq!(kp_signal_bytes, &reinterpret_signal.to_arr()[..]);
prop_assert_eq!(kp_x25519_bytes, &reinterpret_x25519.to_arr()[..]);
}
#[test]
fn test_signal_as_x25519(kp_signal in SignalKeyPair::uniform_keypair_strategy()) {
let kp: X25519KeyPair = X25519KeyPair::from_bytes(&kp_signal.to_arr()).unwrap();
let pk = kp.public();
prop_assert!(X25519KeyPair::check_public_key(pk.clone()).is_ok());
let sk = kp.private();
prop_assert_eq!(&X25519KeyPair::public_from_private(sk), pk);
}
#[test]
fn test_x25519_as_signal(kp_x25519 in X25519KeyPair::uniform_keypair_strategy()) {
let kp: SignalKeyPair = SignalKeyPair::from_bytes(&kp_x25519.to_arr()).unwrap();
let pk = kp.public();
prop_assert!(SignalKeyPair::check_public_key(pk.clone()).is_ok());
let sk = kp.private();
prop_assert_eq!(&SignalKeyPair::public_from_private(sk), pk);
}
}
}