Add a variant to MessageVerificationError

manul/src/session/echo.rs

@@ -189,6 +189,9 @@ where
                 Err(MessageVerificationError::InvalidSignature) => {
                     return Err(EchoRoundError::InvalidEcho(sender.clone()).into())
                 }
+                Err(MessageVerificationError::SignatureMismatch) => {
+                    return Err(EchoRoundError::InvalidEcho(sender.clone()).into())
+                }
             };
 
             // `from` sent us a correctly signed message but from another round or another session.

manul/src/session/evidence.rs

@@ -29,6 +29,9 @@ impl From<MessageVerificationError> for EvidenceError {
         match error {
             MessageVerificationError::Local(error) => Self::Local(error),
             MessageVerificationError::InvalidSignature => Self::InvalidEvidence("Invalid message signature".into()),
+            MessageVerificationError::SignatureMismatch => {
+                Self::InvalidEvidence("The signature does not match the payload".into())
+            }
         }
     }
 }
@@ -259,6 +262,7 @@ where
             Err(MessageVerificationError::Local(error)) => return Err(EvidenceError::Local(error)),
             // The message was indeed incorrectly signed - fault proven
             Err(MessageVerificationError::InvalidSignature) => return Ok(()),
+            Err(MessageVerificationError::SignatureMismatch) => return Ok(()),
         };
 
         // `from` sent us a correctly signed message but from another round or another session.

manul/src/session/message.rs

@@ -36,7 +36,10 @@ impl SerializedSignature {
 #[derive(Debug, Clone)]
 pub(crate) enum MessageVerificationError {
     Local(LocalError),
+    /// The signature could not be deserialized.
     InvalidSignature,
+    /// The signature does not match the signed payload.
+    SignatureMismatch,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
@@ -127,7 +130,7 @@ where
                 message_with_metadata: self.message_with_metadata,
             })
         } else {
-            Err(MessageVerificationError::InvalidSignature)
+            Err(MessageVerificationError::SignatureMismatch)
         }
     }
 }

manul/src/session/session.rs

@@ -281,6 +281,10 @@ where
         let verified_message = match checked_message.verify::<P, SP>(from) {
             Ok(verified_message) => verified_message,
             Err(MessageVerificationError::InvalidSignature) => {
+                accum.register_unprovable_error(from, RemoteError::new("The signature could not be deserialized"))?;
+                return Ok(None);
+            }
+            Err(MessageVerificationError::SignatureMismatch) => {
                 accum.register_unprovable_error(from, RemoteError::new("Message verification failed"))?;
                 return Ok(None);
             }