diff --git a/src/messaging/component.cairo b/src/messaging/component.cairo
index 92758c0..29f18c5 100644
--- a/src/messaging/component.cairo
+++ b/src/messaging/component.cairo
@@ -168,20 +168,14 @@ mod messaging_cpt {
             let nonce = self.sn_to_appc_nonce.read() + 1;
             self.sn_to_appc_nonce.write(nonce);
 
+            let from = starknet::get_caller_address();
             let message_hash = hash::compute_message_hash_sn_to_appc(
-                nonce, to_address, selector, payload
+                from, to_address, selector, payload, nonce
             );
 
             self
                 .emit(
-                    MessageSent {
-                        message_hash,
-                        from: starknet::get_caller_address(),
-                        to: to_address,
-                        selector,
-                        nonce,
-                        payload,
-                    }
+                    MessageSent { message_hash, from, to: to_address, selector, nonce, payload, }
                 );
 
             self.sn_to_appc_messages.write(message_hash, nonce);
@@ -244,7 +238,7 @@ mod messaging_cpt {
             let from = starknet::get_caller_address();
 
             let message_hash = hash::compute_message_hash_sn_to_appc(
-                nonce, to_address, selector, payload
+                from, to_address, selector, payload, nonce
             );
 
             assert(
@@ -273,7 +267,7 @@ mod messaging_cpt {
             let from = starknet::get_caller_address();
 
             let message_hash = hash::compute_message_hash_sn_to_appc(
-                nonce, to_address, selector, payload
+                from, to_address, selector, payload, nonce
             );
 
             assert(
@@ -366,7 +360,7 @@ mod messaging_cpt {
                         let nonce = *m.nonce;
 
                         let message_hash = hash::compute_message_hash_sn_to_appc(
-                            nonce, to, selector, payload
+                            from, to, selector, payload, nonce
                         );
                         assert(
                             self.sn_to_appc_messages.read(message_hash).is_non_zero(),
diff --git a/src/messaging/hash.cairo b/src/messaging/hash.cairo
index 67cd408..7d8633a 100644
--- a/src/messaging/hash.cairo
+++ b/src/messaging/hash.cairo
@@ -9,19 +9,26 @@ use starknet::ContractAddress;
 ///
 /// # Arguments
 ///
-/// * `nonce` - Nonce of the message.
+/// * `from_address` - Contract address of the message sender on the Appchain.
 /// * `to_address` - Contract address to send the message to on the Appchain.
 /// * `selector` - The `l1_handler` function selector of the contract on the Appchain
 ///                to execute.
 /// * `payload` - The message payload.
+/// * `nonce` - Nonce of the message.
 ///
 /// # Returns
 ///
 /// The hash of the message from Starknet to the Appchain.
 fn compute_message_hash_sn_to_appc(
-    nonce: felt252, to_address: ContractAddress, selector: felt252, payload: Span<felt252>
+    from_address: ContractAddress,
+    to_address: ContractAddress,
+    selector: felt252,
+    payload: Span<felt252>,
+    nonce: felt252
 ) -> felt252 {
-    let mut hash_data = array![nonce, to_address.into(), selector,];
+    let mut hash_data = array![
+        from_address.into(), to_address.into(), nonce, selector, payload.len().into(),
+    ];
 
     let mut i = 0_usize;
     loop {
diff --git a/src/messaging/tests/test_messaging.cairo b/src/messaging/tests/test_messaging.cairo
index 7dd1963..2a9ef68 100644
--- a/src/messaging/tests/test_messaging.cairo
+++ b/src/messaging/tests/test_messaging.cairo
@@ -190,7 +190,7 @@ fn sn_to_appchain_messages_ok() {
 
     // Calculate the message_hash
     let message_hash = hash::compute_message_hash_sn_to_appc(
-        nonce: 1, to_address: to, :selector, payload: payload.span()
+        from_address: from, to_address: to, :selector, payload: payload.span(), nonce: 1
     );
     let is_pending_before = mock.sn_to_appchain_messages(message_hash);
     assert(
@@ -413,7 +413,7 @@ fn process_messages_to_appchain_ok() {
     };
 
     let _message_hash = hash::compute_message_hash_sn_to_appc(
-        m.nonce, m.to_address, m.selector, m.payload
+        m.from_address, m.to_address, m.selector, m.payload, m.nonce
     );
 
     let messages = array![m].span();