feat: make public l1tol2 message consumption take leafIndex (#5805)

AztecProtocol · Apr 19, 2024 · ec5da7c · ec5da7c
1 parent 8fe89f8
commit ec5da7c
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Showing 3 changed files with 21 additions and 4 deletions.
diff --git a/aztec/src/context/avm_context.nr b/aztec/src/context/avm_context.nr
@@ -1,3 +1,4 @@
+use crate::hash::{compute_secret_hash, compute_message_hash, compute_message_nullifier};
 use dep::protocol_types::{
     address::{AztecAddress, EthAddress},
     constants::{L1_TO_L2_MESSAGE_LENGTH, NESTED_CALL_L2_GAS_BUFFER}, header::Header
@@ -128,8 +129,23 @@ impl PublicContextInterface for AvmContext {
         assert(false, "'push_unencrypted_log' not required for avm - use emit_unencrypted_log!");
     }
 
-    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress) {
-        assert(false, "'consume_l1_to_l2_message' not implemented!");
+    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress, leaf_index: Field) {
+        let secret_hash = compute_secret_hash(secret);
+        let message_hash = compute_message_hash(
+            sender,
+            self.chain_id(),
+            /*recipient=*/self.this_address(),
+            self.version(),
+            content,
+            secret_hash
+        );
+        let nullifier = compute_message_nullifier(message_hash, secret, leaf_index);
+
+        assert(!self.nullifier_exists(nullifier, self.this_address()), "L1-to-L2 message is already nullified");
+        assert(self.l1_to_l2_msg_exists(message_hash, leaf_index), "Tried to consume nonexistent L1-to-L2 message");
+
+        // Push nullifier (and the "commitment" corresponding to this can be "empty")
+        self.push_new_nullifier(nullifier, 0);
     }
 
     fn message_portal(&mut self, recipient: EthAddress, content: Field) {

diff --git a/aztec/src/context/interface.nr b/aztec/src/context/interface.nr
@@ -33,7 +33,7 @@ trait PublicContextInterface {
     fn fee_per_l1_gas(self) -> Field;
     fn fee_per_l2_gas(self) -> Field;
     fn message_portal(&mut self, recipient: EthAddress, content: Field);
-    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress);
+    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress, leaf_index: Field);
     fn emit_unencrypted_log<T>(&mut self, log: T);
     // TODO(1165) Merge push_unencrypted_log into emit_unencrypted_log, since oracle call
     // in PublicContext will no longer be needed for extracting log hash

diff --git a/aztec/src/context/public_context.nr b/aztec/src/context/public_context.nr
@@ -263,7 +263,8 @@ impl PublicContextInterface for PublicContext {
 
     // We can consume message with a secret in public context because the message cannot be modified and therefore
     // there is no front-running risk (e.g. somebody could front run you to claim your tokens to your address).
-    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress) {
+    // Leaf index is not used in public context, but it is used in the AVMContext which will replace it.
+    fn consume_l1_to_l2_message(&mut self, content: Field, secret: Field, sender: EthAddress, _leaf_index: Field) {
         let this = (*self).this_address();
         let nullifier = process_l1_to_l2_message(
             self.historical_header.state.l1_to_l2_message_tree.root,