little error in initialiser deserialisation

Author: iquerejeta

mithril-core/src/stm.rs

@@ -365,13 +365,13 @@ where
 
         let mut u64_bytes = [0u8; 8];
         u64_bytes.copy_from_slice(&bytes[hash_size..hash_size + 8]);
-        let nr_leaves = usize::from_be_bytes(u64_bytes);
+        let nr_leaves = u64::from_be_bytes(u64_bytes);
         u64_bytes.copy_from_slice(&bytes[hash_size + 8..hash_size + 16]);
         let total_stake = u64::from_be_bytes(u64_bytes);
 
         let mt_commitment = MerkleTreeCommitment::<D> {
             root,
-            nr_leaves,
+            nr_leaves: nr_leaves as usize,
             hasher: Default::default(),
         };
 
@@ -385,7 +385,7 @@ where
     pub fn to_bytes(&self) -> Vec<u8> {
         let mut output = Vec::new();
         output.extend_from_slice(&self.mt_commitment.root);
-        output.extend_from_slice(&self.mt_commitment.nr_leaves.to_be_bytes());
+        output.extend_from_slice(&(self.mt_commitment.nr_leaves as u64).to_be_bytes());
         output.extend_from_slice(&self.total_stake.to_be_bytes());
         output
     }
@@ -659,7 +659,7 @@ impl StmInitializer {
         let party_id = u64::from_be_bytes(u64_bytes);
         u64_bytes.copy_from_slice(&bytes[8..16]);
         let stake = u64::from_be_bytes(u64_bytes);
-        let params = StmParameters::from_bytes(&bytes[16..])?;
+        let params = StmParameters::from_bytes(&bytes[16..40])?;
         let sk = SigningKey::from_bytes(&bytes[40..])?;
         let pk = StmVerificationKeyPoP::from_bytes(&bytes[72..])?;
 
@@ -1149,6 +1149,15 @@ mod tests {
     proptest! {
         #![proptest_config(ProptestConfig::with_cases(10))]
 
+        #[test]
+        fn test_parameters_serialize_deserialize(m in any::<u64>(), k in any::<u64>(), phi_f in any::<f64>()) {
+            let params = StmParameters { m, k, phi_f };
+
+            let bytes = params.to_bytes();
+            let deserialised = StmParameters::from_bytes(&bytes);
+            assert!(deserialised.is_ok())
+        }
+
         #[test]
         fn test_initializer_serialize_deserialize(seed in any::<[u8;32]>()) {
             let mut rng = ChaCha20Rng::from_seed(seed);
@@ -1157,6 +1166,9 @@ mod tests {
             let stake = rng.next_u64();
             let initializer = StmInitializer::setup(params, pid, stake, &mut rng);
 
+            let bytes = initializer.to_bytes();
+            assert!(StmInitializer::from_bytes(&bytes).is_ok());
+
             let bytes = bincode::serialize(&initializer).unwrap();
             assert!(bincode::deserialize::<StmInitializer>(&bytes).is_ok())
         }