diff --git a/substrate/tendermint/src/ext.rs b/substrate/tendermint/src/ext.rs
index 8bc19f8c..94b95b61 100644
--- a/substrate/tendermint/src/ext.rs
+++ b/substrate/tendermint/src/ext.rs
@@ -104,7 +104,7 @@ pub enum BlockError {
 /// Trait representing a Block.
 pub trait Block: Send + Sync + Clone + PartialEq + Debug + Encode + Decode {
   // Type used to identify blocks. Presumably a cryptographic hash of the block.
-  type Id: Send + Sync + Copy + Clone + PartialEq + Debug + Encode + Decode;
+  type Id: Send + Sync + Copy + Clone + PartialEq + AsRef<[u8]> + Debug + Encode + Decode;
 
   /// Return the deterministic, unique ID for this block.
   fn id(&self) -> Self::Id;
diff --git a/substrate/tendermint/src/lib.rs b/substrate/tendermint/src/lib.rs
index 75f9de30..b35c56c9 100644
--- a/substrate/tendermint/src/lib.rs
+++ b/substrate/tendermint/src/lib.rs
@@ -301,6 +301,7 @@ impl<N: Network + 'static> TendermintMachine<N> {
         // Check if it has gotten a sufficient amount of precommits
         let (participants, weight) = self
           .log
+          // Use a junk signature since message equality is irrelevant to the signature
           .message_instances(round, Data::Precommit(Some((block.id(), self.signer.sign(&[])))));
 
         let threshold = self.weights.threshold();
@@ -324,7 +325,7 @@ impl<N: Network + 'static> TendermintMachine<N> {
     msg: Message<N::ValidatorId, N::Block, <N::SignatureScheme as SignatureScheme>::Signature>,
   ) -> Result<Option<N::Block>, TendermintError<N::ValidatorId>> {
     if let Data::Precommit(Some((id, sig))) = &msg.data {
-      if !self.signer.verify(msg.sender, &id.encode(), sig.clone()) {
+      if !self.signer.verify(msg.sender, id.as_ref(), sig.clone()) {
         Err(TendermintError::Malicious(msg.sender))?;
       }
     }
@@ -433,7 +434,7 @@ impl<N: Network + 'static> TendermintMachine<N> {
                 self
                   .broadcast(Data::Precommit(Some((
                     block.id(),
-                    self.signer.sign(&block.id().encode()),
+                    self.signer.sign(block.id().as_ref()),
                   ))))
                   .await,
               );
diff --git a/substrate/tendermint/tests/ext.rs b/substrate/tendermint/tests/ext.rs
index 16bf2bce..21e35187 100644
--- a/substrate/tendermint/tests/ext.rs
+++ b/substrate/tendermint/tests/ext.rs
@@ -7,7 +7,7 @@ use tokio::sync::RwLock;
 use tendermint_machine::{ext::*, SignedMessage, TendermintMachine, TendermintHandle};
 
 type TestValidatorId = u16;
-type TestBlockId = u32;
+type TestBlockId = [u8; 4];
 
 struct TestSignatureScheme(u16);
 impl SignatureScheme for TestSignatureScheme {
@@ -114,7 +114,7 @@ impl Network for TestNetwork {
     dbg!("Adding ", &block);
     assert!(block.valid.is_ok());
     assert!(self.verify_commit(block.id(), &commit));
-    TestBlock { id: block.id + 1, valid: Ok(()) }
+    TestBlock { id: (u32::from_le_bytes(block.id) + 1).to_le_bytes(), valid: Ok(()) }
   }
 }
 
@@ -129,7 +129,7 @@ impl TestNetwork {
           TestNetwork(i, arc.clone()),
           i,
           BlockNumber(1),
-          TestBlock { id: 1, valid: Ok(()) },
+          TestBlock { id: 1u32.to_le_bytes(), valid: Ok(()) },
         ));
       }
     }