diff --git a/src/commit.rs b/src/commit.rs
index 6d28ece..29cfc01 100644
--- a/src/commit.rs
+++ b/src/commit.rs
@@ -306,8 +306,13 @@ fn process_validation(
             .validation_tokens
             .extend(commit_msg.validation_tokens.iter());
 
-        state_to_update.validation_tokens.sort_unstable();
-        state_to_update.validation_tokens.dedup();
+        // Sort by public key to group validations by signer
+        state_to_update.validation_tokens.sort_unstable_by_key(|proof| proof.get_key());
+
+        // Remove duplicates where same key validates same message
+        state_to_update.validation_tokens.dedup_by(|a, b| {
+            a.get_key() == b.get_key() && a.get_message() == b.get_message()
+        });
     }
 
     let state_to_validate = updated_process.get_state_for_id(&new_state_id)?;