Added a dedicated marker trait for supported RNG sources

Author: Joni

src/handshakestate/mod.rs

@@ -1,5 +1,4 @@
 use arrayvec::ArrayVec;
-use rand_core::{CryptoRng, RngCore};
 use zeroize::Zeroize;
 
 use crate::bytearray::ByteArray;
@@ -8,7 +7,7 @@ use crate::constants::{MAX_PSKS, PSK_LEN};
 use crate::error::{HandshakeError, HandshakeResult};
 use crate::handshakepattern::{HandshakePattern, Token};
 use crate::symmetricstate::SymmetricState;
-use crate::traits::{Cipher, Hash};
+use crate::traits::{Cipher, Hash, Rng};
 use crate::KeyPair;
 
 pub mod dual_layer;
@@ -32,7 +31,7 @@ pub(crate) struct HandshakeInternals<'a, C, H, RNG, K, P, EK, EP>
 where
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
     K: ByteArray,
     P: ByteArray,
     EK: ByteArray,
@@ -56,7 +55,7 @@ impl<'a, C, H, RNG, K, P, EK, EP> HandshakeInternals<'a, C, H, RNG, K, P, EK, EP
 where
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
     K: ByteArray,
     P: ByteArray,
     EK: ByteArray,

src/handshakestate/nq.rs

@@ -3,7 +3,6 @@
 use core::fmt::Write;
 
 use arrayvec::{ArrayString, ArrayVec};
-use rand_core::{CryptoRng, RngCore};
 
 use super::HandshakeInternals;
 use crate::bytearray::ByteArray;
@@ -12,7 +11,7 @@ use crate::error::{HandshakeError, HandshakeResult};
 use crate::handshakepattern::{HandshakePattern, Token};
 use crate::handshakestate::HandshakeStatus;
 use crate::symmetricstate::SymmetricState;
-use crate::traits::{Cipher, Dh, Handshaker, HandshakerInternal, Hash};
+use crate::traits::{Cipher, Dh, Handshaker, HandshakerInternal, Hash, Rng};
 use crate::KeyPair;
 
 /// Non-post-quantum Noise handshake
@@ -21,7 +20,7 @@ where
     DH: Dh,
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     // Internal, we can live with this
     #[allow(clippy::type_complexity)]
@@ -34,7 +33,7 @@ where
     DH: Dh,
     CIPHER: Cipher,
     HASH: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     /// Initialize new non-post-quantum handshake
     ///
@@ -211,7 +210,7 @@ where
     DH: Dh,
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     fn status(&self) -> HandshakeStatus {
         self.internals.status()
@@ -397,7 +396,7 @@ where
     DH: Dh,
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     type E = DH::PubKey;
     type S = DH::PubKey;

src/handshakestate/pq.rs

@@ -3,7 +3,6 @@
 use core::fmt::Write;
 
 use arrayvec::{ArrayString, ArrayVec};
-use rand_core::{CryptoRng, RngCore};
 
 use super::HandshakeInternals;
 use crate::bytearray::ByteArray;
@@ -13,7 +12,7 @@ use crate::error::{HandshakeError, HandshakeResult};
 use crate::handshakepattern::{HandshakePattern, Token};
 use crate::handshakestate::HandshakeStatus;
 use crate::symmetricstate::SymmetricState;
-use crate::traits::{Cipher, Handshaker, HandshakerInternal, Hash, Kem};
+use crate::traits::{Cipher, Handshaker, HandshakerInternal, Hash, Kem, Rng};
 use crate::KeyPair;
 
 /// Post-quantum Noise handshake
@@ -23,7 +22,7 @@ where
     SKEM: Kem,
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     // Internal, we can live with this
     #[allow(clippy::type_complexity)]
@@ -45,7 +44,7 @@ where
     SKEM: Kem,
     CIPHER: Cipher,
     HASH: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     /// Initialize new post-quantum handshake
     ///
@@ -190,7 +189,7 @@ where
     SKEM: Kem,
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     fn status(&self) -> HandshakeStatus {
         self.internals.status()
@@ -434,7 +433,7 @@ where
     SKEM: Kem,
     C: Cipher,
     H: Hash,
-    RNG: RngCore + CryptoRng,
+    RNG: Rng,
 {
     type E = EKEM::PubKey;
     type S = SKEM::PubKey;

src/traits.rs

@@ -1,7 +1,7 @@
 //! Common traits used throughout the crate
 
 use arrayvec::ArrayString;
-use rand_core::{CryptoRng, RngCore};
+pub use rand_core::{CryptoRng, RngCore};
 use zeroize::Zeroize;
 
 use crate::bytearray::ByteArray;
@@ -19,6 +19,16 @@ pub trait CryptoComponent {
     fn name() -> &'static str;
 }
 
+/// Common trait for compatible RNG sources
+///
+/// Automatically implemented for all types that implement:
+/// * [`RngCore`]
+/// * [`CryptoRng`]
+pub trait Rng: RngCore + CryptoRng {}
+
+/// Automatic implementation for all supported types
+impl<T: RngCore + CryptoRng> Rng for T {}
+
 /// Common trait for all Diffie-Hellman algorithms
 pub trait Dh: CryptoComponent {
     /// Private key type
@@ -29,9 +39,7 @@ pub trait Dh: CryptoComponent {
     type Output: ByteArray;
 
     /// Generate a keypair
-    fn genkey<R: RngCore + CryptoRng>(
-        rng: &mut R,
-    ) -> DhResult<KeyPair<Self::PubKey, Self::PrivateKey>>;
+    fn genkey<R: Rng>(rng: &mut R) -> DhResult<KeyPair<Self::PubKey, Self::PrivateKey>>;
 
     /// Extract public key from given private key
     fn pubkey(k: &Self::PrivateKey) -> Self::PubKey;
@@ -52,15 +60,10 @@ pub trait Kem: CryptoComponent {
     type Ss: ByteArray;
 
     /// Generate a keypair
-    fn genkey<R: RngCore + CryptoRng>(
-        rng: &mut R,
-    ) -> KemResult<KeyPair<Self::PubKey, Self::SecretKey>>;
+    fn genkey<R: Rng>(rng: &mut R) -> KemResult<KeyPair<Self::PubKey, Self::SecretKey>>;
 
     /// Encapsulate a public key and return the ciphertext and shared secret
-    fn encapsulate<R: RngCore + CryptoRng>(
-        pk: &[u8],
-        rng: &mut R,
-    ) -> KemResult<(Self::Ct, Self::Ss)>;
+    fn encapsulate<R: Rng>(pk: &[u8], rng: &mut R) -> KemResult<(Self::Ct, Self::Ss)>;
 
     /// Decapsulate ciphertext with secret key and return the shared secret
     fn decapsulate(ct: &[u8], sk: &[u8]) -> KemResult<Self::Ss>;