add decoding impl

rust/catalyst-voting/src/crypto/ed25519/decoding.rs

@@ -1,10 +1,31 @@
 //! `Ed25519` objects decoding implementation
 
+use anyhow::anyhow;
 use ed25519_dalek::{
-    Signature as Ed25519Signature, VerifyingKey, PUBLIC_KEY_LENGTH, SIGNATURE_LENGTH,
+    Signature as Ed25519Signature, SigningKey, VerifyingKey, PUBLIC_KEY_LENGTH, SECRET_KEY_LENGTH,
+    SIGNATURE_LENGTH,
 };
 
-use super::{PublicKey, Signature};
+use super::{PrivateKey, PublicKey, Signature};
+
+impl PrivateKey {
+    /// `PrivateKey` bytes size
+    pub const BYTES_SIZE: usize = SECRET_KEY_LENGTH;
+
+    /// Convert this `PrivateKey` to its underlying sequence of bytes.
+    #[must_use]
+    pub fn to_bytes(&self) -> [u8; Self::BYTES_SIZE] {
+        self.0.to_bytes()
+    }
+
+    /// Attempt to construct a `PrivateKey` from a byte representation.
+    ///
+    /// # Errors
+    ///   - Cannot decode public key.
+    pub fn from_bytes(bytes: &[u8; Self::BYTES_SIZE]) -> Self {
+        Self(SigningKey::from_bytes(bytes))
+    }
+}
 
 impl PublicKey {
     /// `PublicKey` bytes size
@@ -21,7 +42,9 @@ impl PublicKey {
     /// # Errors
     ///   - Cannot decode public key.
     pub fn from_bytes(bytes: &[u8; Self::BYTES_SIZE]) -> anyhow::Result<Self> {
-        Ok(Self(VerifyingKey::from_bytes(bytes)?))
+        Ok(Self(
+            VerifyingKey::from_bytes(bytes).map_err(|_| anyhow!("Cannot decode public key."))?,
+        ))
     }
 }
 

rust/catalyst-voting/src/vote_protocol/committee/decoding.rs

@@ -0,0 +1,66 @@
+//! committee objects decoding implementation
+
+use anyhow::anyhow;
+
+use super::{ElectionPublicKey, ElectionSecretKey, GroupElement, Scalar};
+
+impl ElectionSecretKey {
+    /// `ElectionSecretKey` bytes size
+    pub const BYTES_SIZE: usize = Scalar::BYTES_SIZE;
+
+    /// Convert this `ElectionSecretKey` to its underlying sequence of bytes.
+    #[must_use]
+    pub fn to_bytes(&self) -> [u8; Self::BYTES_SIZE] {
+        self.0.to_bytes()
+    }
+
+    /// Attempt to construct a `ElectionSecretKey` from a byte representation.
+    ///
+    /// # Errors
+    ///   - Cannot decode election secret key.
+    pub fn from_bytes(bytes: [u8; Self::BYTES_SIZE]) -> anyhow::Result<Self> {
+        Ok(Self(Scalar::from_bytes(bytes).map_err(|_| {
+            anyhow!("Cannot decode election secret key.")
+        })?))
+    }
+}
+
+impl ElectionPublicKey {
+    /// `ElectionPublicKey` bytes size
+    pub const BYTES_SIZE: usize = GroupElement::BYTES_SIZE;
+
+    /// Convert this `ElectionPublicKey` to its underlying sequence of bytes.
+    #[must_use]
+    pub fn to_bytes(&self) -> [u8; Self::BYTES_SIZE] {
+        self.0.to_bytes()
+    }
+
+    /// Attempt to construct a `ElectionPublicKey` from a byte representation.
+    ///
+    /// # Errors
+    ///   - Cannot decode election public key.
+    pub fn from_bytes(bytes: &[u8; Self::BYTES_SIZE]) -> anyhow::Result<Self> {
+        Ok(Self(
+            GroupElement::from_bytes(bytes).map_err(|_| anyhow!("Cannot decode public key."))?,
+        ))
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use test_strategy::proptest;
+
+    use super::*;
+
+    #[proptest]
+    fn election_keys_to_bytes_from_bytes_test(sk1: ElectionSecretKey) {
+        let bytes = sk1.to_bytes();
+        let sk2 = ElectionSecretKey::from_bytes(bytes).unwrap();
+        assert_eq!(sk1, sk2);
+
+        let pk1 = sk1.public_key();
+        let bytes = pk1.to_bytes();
+        let pk2 = ElectionPublicKey::from_bytes(&bytes).unwrap();
+        assert_eq!(pk1, pk2);
+    }
+}

rust/catalyst-voting/src/vote_protocol/committee.rs → rust/catalyst-voting/src/vote_protocol/committee/mod.rs

@@ -1,5 +1,7 @@
 //! Module containing all primitives related to the committee.
 
+mod decoding;
+
 use rand_core::CryptoRngCore;
 
 use crate::crypto::{