feat: Add first version of kernel reset circuit (AztecProtocol#6393)

This PR moves the resetting logic from tail circuits to their own
circuit, the first version of the reset. Right now it resets the whole
TX and is just run before the tail. The idea is to make the data
structures of this reset generic and create different sizes of it, and
start using it when necessary between the iterations of the inner kernel
circuit.

noir-projects/noir-protocol-circuits/Nargo.toml

@@ -9,6 +9,8 @@ members = [
     "crates/private-kernel-init-simulated",
     "crates/private-kernel-inner",
     "crates/private-kernel-inner-simulated",
+    "crates/private-kernel-reset",
+    "crates/private-kernel-reset-simulated",
     "crates/private-kernel-tail",
     "crates/private-kernel-tail-simulated",
     "crates/private-kernel-tail-to-public",

noir-projects/noir-protocol-circuits/crates/private-kernel-lib/src/kernel_circuit_public_inputs_composer.nr

@@ -1,4 +1,3 @@
-use dep::reset_kernel_lib::verify_squashed_transient_note_hashes_and_nullifiers;
 use dep::types::{
     abis::{
     private_kernel_data::PrivateKernelData,
@@ -23,12 +22,7 @@ fn asc_sort_by_counters<T>(a: T, b: T) -> bool where T: Ordered {
 struct KernelCircuitPublicInputsComposer {
     public_inputs: PrivateKernelCircuitPublicInputsBuilder,
     previous_kernel: PrivateKernelData,
-    // Final data
-    note_hashes: [ScopedNoteHash; MAX_NEW_NOTE_HASHES_PER_TX],
-    nullifiers: [ScopedNullifier; MAX_NEW_NULLIFIERS_PER_TX],
     // Hints
-    transient_nullifier_indexes_for_note_hashes: [u64; MAX_NEW_NOTE_HASHES_PER_TX],
-    transient_note_hash_indexes_for_nullifiers: [u64; MAX_NEW_NULLIFIERS_PER_TX],
     sorted_note_hashes: [ScopedNoteHash; MAX_NEW_NOTE_HASHES_PER_TX],
     sorted_note_hashes_indexes: [u64; MAX_NEW_NOTE_HASHES_PER_TX],
     sorted_nullifiers: [ScopedNullifier; MAX_NEW_NULLIFIERS_PER_TX],
@@ -42,10 +36,6 @@ struct KernelCircuitPublicInputsComposer {
 impl KernelCircuitPublicInputsComposer {
     pub fn new(
         previous_kernel: PrivateKernelData,
-        note_hashes: [ScopedNoteHash; MAX_NEW_NOTE_HASHES_PER_TX],
-        nullifiers: [ScopedNullifier; MAX_NEW_NULLIFIERS_PER_TX],
-        transient_nullifier_indexes_for_note_hashes: [u64; MAX_NEW_NOTE_HASHES_PER_TX],
-        transient_note_hash_indexes_for_nullifiers: [u64; MAX_NEW_NULLIFIERS_PER_TX],
         sorted_note_hashes: [ScopedNoteHash; MAX_NEW_NOTE_HASHES_PER_TX],
         sorted_note_hashes_indexes: [u64; MAX_NEW_NOTE_HASHES_PER_TX],
         sorted_nullifiers: [ScopedNullifier; MAX_NEW_NULLIFIERS_PER_TX],
@@ -60,10 +50,6 @@ impl KernelCircuitPublicInputsComposer {
         KernelCircuitPublicInputsComposer {
             public_inputs,
             previous_kernel,
-            note_hashes,
-            nullifiers,
-            transient_nullifier_indexes_for_note_hashes,
-            transient_note_hash_indexes_for_nullifiers,
             sorted_note_hashes,
             sorted_note_hashes_indexes,
             sorted_nullifiers,
@@ -79,6 +65,7 @@ impl KernelCircuitPublicInputsComposer {
         assert_eq(
             array_length(self.previous_kernel.public_inputs.end.private_call_stack), 0, "Private call stack must be empty when executing the tail circuit"
         );
+        self.verify_empty_validation_requests();
 
         self.propagate_rollup_validation_requests();
 
@@ -88,8 +75,7 @@ impl KernelCircuitPublicInputsComposer {
 
         self.propagate_fee_payer();
 
-        // TODO: Should be done in a reset circuit.
-        self.squash_transient_data();
+        self.verify_no_transient_data();
 
         self.silo_values();
 
@@ -236,26 +222,28 @@ impl KernelCircuitPublicInputsComposer {
         self.public_inputs.fee_payer = self.previous_kernel.public_inputs.fee_payer;
     }
 
-    fn squash_transient_data(&mut self) {
-        verify_squashed_transient_note_hashes_and_nullifiers(
-            self.public_inputs.end.new_note_hashes.storage,
-            self.public_inputs.end.new_nullifiers.storage,
-            self.note_hashes,
-            self.nullifiers,
-            self.transient_nullifier_indexes_for_note_hashes,
-            self.transient_note_hash_indexes_for_nullifiers
-        );
-
-        // Currently all the transient note hashes and nullifiers must be cleared in the tail circuits.
+    fn verify_no_transient_data(self) {
+        // Currently all the transient note hashes and nullifiers must be cleared in the reset circuits.
         // Check that the propagated note hashes don't link to a nullifier, and vice versa.
-        for i in 0..self.note_hashes.len() {
-            assert(self.note_hashes[i].nullifier_counter == 0, "Unresolved transient note hash");
+        for note_hash in self.public_inputs.end.new_note_hashes.storage {
+            assert(note_hash.nullifier_counter == 0, "Unresolved transient note hash");
         }
-        for i in 0..self.nullifiers.len() {
-            assert(self.nullifiers[i].nullified_note_hash() == 0, "Unresolved transient nullifier");
+        for new_nullifier in self.public_inputs.end.new_nullifiers.storage {
+            assert(new_nullifier.nullified_note_hash() == 0, "Unresolved transient nullifier");
         }
+    }
+
+    fn verify_empty_validation_requests(self) {
+        assert_eq(
+            array_length(self.previous_kernel.public_inputs.validation_requests.note_hash_read_requests), 0, "Non empty note hash read requests"
+        );
 
-        self.public_inputs.end.new_note_hashes = array_to_bounded_vec(self.note_hashes);
-        self.public_inputs.end.new_nullifiers = array_to_bounded_vec(self.nullifiers);
+        assert_eq(
+            array_length(self.previous_kernel.public_inputs.validation_requests.nullifier_read_requests), 0, "Non empty nullifier read requests"
+        );
+
+        assert_eq(
+            array_length(self.previous_kernel.public_inputs.validation_requests.nullifier_key_validation_requests), 0, "Non empty nullifier key validation requests"
+        );
     }
 }

noir-projects/noir-protocol-circuits/crates/private-kernel-lib/src/lib.nr

@@ -6,8 +6,10 @@ mod private_kernel_inner;
 mod private_kernel_tail;
 mod private_kernel_tail_to_public;
 mod tests;
+mod private_kernel_reset;
 
 use private_kernel_init::PrivateKernelInitCircuitPrivateInputs;
 use private_kernel_inner::PrivateKernelInnerCircuitPrivateInputs;
+use private_kernel_reset::PrivateKernelResetCircuitPrivateInputs;
 use private_kernel_tail::PrivateKernelTailCircuitPrivateInputs;
 use private_kernel_tail_to_public::PrivateKernelTailToPublicCircuitPrivateInputs;