refactor: passing partial note logs through transient storage (#9356)

noir-projects/aztec-nr/aztec/src/encrypted_logs/encrypted_event_emission.nr

@@ -1,5 +1,5 @@
 use crate::{
-    context::PrivateContext, encrypted_logs::payload::compute_encrypted_log,
+    context::PrivateContext, encrypted_logs::payload::compute_private_log_payload,
     event::event_interface::EventInterface, keys::getters::get_ovsk_app, oracle::random::random,
 };
 use dep::protocol_types::{
@@ -8,7 +8,8 @@ use dep::protocol_types::{
     public_keys::{IvpkM, OvpkM},
 };
 
-fn compute_raw_event_log<Event, let N: u32>(
+/// Computes private event log payload and a log hash
+fn compute_payload_and_hash<Event, let N: u32>(
     context: PrivateContext,
     event: Event,
     randomness: Field,
@@ -22,13 +23,22 @@ where
 {
     let contract_address: AztecAddress = context.this_address();
     let plaintext = event.private_to_be_bytes(randomness);
-    let encrypted_log: [u8; 416 + N * 32] =
-        compute_encrypted_log(contract_address, ovsk_app, ovpk, ivpk, recipient, plaintext);
+
+    // For event logs we never include public values prefix as there are never any public values
+    let encrypted_log: [u8; 416 + N * 32] = compute_private_log_payload(
+        contract_address,
+        ovsk_app,
+        ovpk,
+        ivpk,
+        recipient,
+        plaintext,
+        false,
+    );
     let log_hash = sha256_to_field(encrypted_log);
     (encrypted_log, log_hash)
 }
 
-unconstrained fn compute_raw_event_log_unconstrained<Event, let N: u32>(
+unconstrained fn compute_payload_and_hash_unconstrained<Event, let N: u32>(
     context: PrivateContext,
     event: Event,
     randomness: Field,
@@ -40,7 +50,7 @@ where
     Event: EventInterface<N>,
 {
     let ovsk_app = get_ovsk_app(ovpk.hash());
-    compute_raw_event_log(context, event, randomness, ovsk_app, ovpk, ivpk, recipient)
+    compute_payload_and_hash(context, event, randomness, ovsk_app, ovpk, ivpk, recipient)
 }
 
 pub fn encode_and_encrypt_event<Event, let N: u32>(
@@ -60,7 +70,7 @@ where
         let randomness = unsafe { random() };
         let ovsk_app: Field = context.request_ovsk_app(ovpk.hash());
         let (encrypted_log, log_hash) =
-            compute_raw_event_log(*context, e, randomness, ovsk_app, ovpk, ivpk, recipient);
+            compute_payload_and_hash(*context, e, randomness, ovsk_app, ovpk, ivpk, recipient);
         context.emit_raw_event_log_with_masked_address(randomness, encrypted_log, log_hash);
     }
 }
@@ -81,7 +91,7 @@ where
         // value generation.
         let randomness = unsafe { random() };
         let (encrypted_log, log_hash) = unsafe {
-            compute_raw_event_log_unconstrained(*context, e, randomness, ovpk, ivpk, recipient)
+            compute_payload_and_hash_unconstrained(*context, e, randomness, ovpk, ivpk, recipient)
         };
         context.emit_raw_event_log_with_masked_address(randomness, encrypted_log, log_hash);
     }
@@ -103,7 +113,7 @@ where
     |e: Event| {
         let ovsk_app: Field = context.request_ovsk_app(ovpk.hash());
         let (encrypted_log, log_hash) =
-            compute_raw_event_log(*context, e, randomness, ovsk_app, ovpk, ivpk, recipient);
+            compute_payload_and_hash(*context, e, randomness, ovsk_app, ovpk, ivpk, recipient);
         context.emit_raw_event_log_with_masked_address(randomness, encrypted_log, log_hash);
     }
 }
@@ -134,7 +144,7 @@ where
         // return the log from this function to the app, otherwise it could try to do stuff with it and then that might
         // be wrong.
         let (encrypted_log, log_hash) = unsafe {
-            compute_raw_event_log_unconstrained(*context, e, randomness, ovpk, ivpk, recipient)
+            compute_payload_and_hash_unconstrained(*context, e, randomness, ovpk, ivpk, recipient)
         };
         context.emit_raw_event_log_with_masked_address(randomness, encrypted_log, log_hash);
     }

noir-projects/aztec-nr/aztec/src/encrypted_logs/encrypted_note_emission.nr

@@ -1,6 +1,6 @@
 use crate::{
     context::PrivateContext,
-    encrypted_logs::payload::compute_encrypted_log,
+    encrypted_logs::payload::compute_private_log_payload,
     keys::getters::get_ovsk_app,
     note::{note_emission::NoteEmission, note_interface::NoteInterface},
 };
@@ -11,14 +11,15 @@ use dep::protocol_types::{
     public_keys::{IvpkM, OvpkM, PublicKeys},
 };
 
-fn compute_raw_note_log<Note, let N: u32>(
+/// Computes private note log payload and a log hash
+fn compute_payload_and_hash<Note, let N: u32>(
     context: PrivateContext,
     note: Note,
     ovsk_app: Field,
     ovpk: OvpkM,
     ivpk: IvpkM,
     recipient: AztecAddress,
-) -> (u32, [u8; 416 + N * 32], Field)
+) -> (u32, [u8; 417 + N * 32], Field)
 where
     Note: NoteInterface<N>,
 {
@@ -33,25 +34,34 @@ where
     let contract_address: AztecAddress = context.this_address();
 
     let plaintext = note.to_be_bytes(storage_slot);
-    let encrypted_log: [u8; 416 + N * 32] =
-        compute_encrypted_log(contract_address, ovsk_app, ovpk, ivpk, recipient, plaintext);
+
+    // For note logs we always include public values prefix
+    let encrypted_log: [u8; 417 + N * 32] = compute_private_log_payload(
+        contract_address,
+        ovsk_app,
+        ovpk,
+        ivpk,
+        recipient,
+        plaintext,
+        true,
+    );
     let log_hash = sha256_to_field(encrypted_log);
 
     (note_hash_counter, encrypted_log, log_hash)
 }
 
-unconstrained fn compute_raw_note_log_unconstrained<Note, let N: u32>(
+unconstrained fn compute_payload_and_hash_unconstrained<Note, let N: u32>(
     context: PrivateContext,
     note: Note,
     ovpk: OvpkM,
     ivpk: IvpkM,
     recipient: AztecAddress,
-) -> (u32, [u8; 416 + N * 32], Field)
+) -> (u32, [u8; 417 + N * 32], Field)
 where
     Note: NoteInterface<N>,
 {
     let ovsk_app = get_ovsk_app(ovpk.hash());
-    compute_raw_note_log(context, note, ovsk_app, ovpk, ivpk, recipient)
+    compute_payload_and_hash(context, note, ovsk_app, ovpk, ivpk, recipient)
 }
 
 // This function seems to be affected by the following Noir bug:
@@ -70,7 +80,7 @@ where
         let ovsk_app: Field = context.request_ovsk_app(ovpk.hash());
 
         let (note_hash_counter, encrypted_log, log_hash) =
-            compute_raw_note_log(*context, e.note, ovsk_app, ovpk, ivpk, recipient);
+            compute_payload_and_hash(*context, e.note, ovsk_app, ovpk, ivpk, recipient);
         context.emit_raw_note_log(note_hash_counter, encrypted_log, log_hash);
     }
 }
@@ -104,38 +114,9 @@ where
         // for the log to be deleted when it shouldn't have (which is fine - they can already make the content be
         // whatever), or cause for the log to not be deleted when it should have (which is also fine - it'll be a log
         // for a note that doesn't exist).
-        let (note_hash_counter, encrypted_log, log_hash) =
-            unsafe { compute_raw_note_log_unconstrained(*context, e.note, ovpk, ivpk, recipient) };
+        let (note_hash_counter, encrypted_log, log_hash) = unsafe {
+            compute_payload_and_hash_unconstrained(*context, e.note, ovpk, ivpk, recipient)
+        };
         context.emit_raw_note_log(note_hash_counter, encrypted_log, log_hash);
     }
 }
-
-/// Encrypts a partial log and emits it. Takes recipient keys on the input and encrypts both the outgoing and incoming
-/// logs for the recipient. This is necessary because in the partial notes flow the outgoing always has to be the same
-/// as the incoming to not leak any information (typically the `from` party finalizing the partial note in public does
-/// not know who the recipient is).
-pub fn encrypt_and_emit_partial_log<let M: u32>(
-    context: &mut PrivateContext,
-    log_plaintext: [u8; M],
-    recipient_keys: PublicKeys,
-    recipient: AztecAddress,
-) {
-    let ovsk_app: Field = context.request_ovsk_app(recipient_keys.ovpk_m.hash());
-
-    let encrypted_log: [u8; 352 + M] = compute_encrypted_log(
-        context.this_address(),
-        ovsk_app,
-        recipient_keys.ovpk_m,
-        recipient_keys.ivpk_m,
-        recipient,
-        log_plaintext,
-    );
-    let log_hash = sha256_to_field(encrypted_log);
-
-    // Unfortunately we need to push a dummy note hash to the context here because a note log requires having
-    // a counter that corresponds to a note hash in the same call.
-    let note_hash_counter = context.side_effect_counter;
-    context.push_note_hash(5);
-
-    context.emit_raw_note_log(note_hash_counter, encrypted_log, log_hash);
-}

noir-projects/aztec-nr/aztec/src/encrypted_logs/payload.nr

@@ -17,13 +17,14 @@ use crate::{
     utils::point::point_to_bytes,
 };
 
-pub fn compute_encrypted_log<let P: u32, let M: u32>(
+fn compute_private_log_payload<let P: u32, let M: u32>(
     contract_address: AztecAddress,
     ovsk_app: Field,
     ovpk: OvpkM,
     ivpk: IvpkM,
     recipient: AztecAddress,
     plaintext: [u8; P],
+    include_public_values_prefix: bool,
 ) -> [u8; M] {
     let (eph_sk, eph_pk) = generate_ephemeral_key_pair();
 
@@ -41,27 +42,39 @@ pub fn compute_encrypted_log<let P: u32, let M: u32>(
         eph_pk,
     );
 
+    // If we include the prefix for number of public values, we need to add 1 byte to the offset
+    let mut offset = if include_public_values_prefix { 1 } else { 0 };
+
     let mut encrypted_bytes: [u8; M] = [0; M];
     // @todo We ignore the tags for now
+    offset += 64;
+
     let eph_pk_bytes = point_to_bytes(eph_pk);
     for i in 0..32 {
-        encrypted_bytes[64 + i] = eph_pk_bytes[i];
+        encrypted_bytes[offset + i] = eph_pk_bytes[i];
     }
+
+    offset += 32;
     for i in 0..48 {
-        encrypted_bytes[96 + i] = incoming_header_ciphertext[i];
-        encrypted_bytes[144 + i] = outgoing_header_ciphertext[i];
+        encrypted_bytes[offset + i] = incoming_header_ciphertext[i];
+        encrypted_bytes[offset + 48 + i] = outgoing_header_ciphertext[i];
     }
+
+    offset += 48 * 2;
     for i in 0..144 {
-        encrypted_bytes[192 + i] = outgoing_body_ciphertext[i];
+        encrypted_bytes[offset + i] = outgoing_body_ciphertext[i];
     }
+
+    offset += 144;
     // Then we fill in the rest as the incoming body ciphertext
-    let size = M - 336;
+    let size = M - offset;
     assert_eq(size, incoming_body_ciphertext.len(), "ciphertext length mismatch");
     for i in 0..size {
-        encrypted_bytes[336 + i] = incoming_body_ciphertext[i];
+        encrypted_bytes[offset + i] = incoming_body_ciphertext[i];
     }
 
     // Current unoptimized size of the encrypted log
+    // empty_prefix (1 byte)
     // incoming_tag (32 bytes)
     // outgoing_tag (32 bytes)
     // eph_pk (32 bytes)
@@ -160,7 +173,8 @@ pub fn compute_outgoing_body_ciphertext(
 
 mod test {
     use crate::encrypted_logs::payload::{
-        compute_encrypted_log, compute_incoming_body_ciphertext, compute_outgoing_body_ciphertext,
+        compute_incoming_body_ciphertext, compute_outgoing_body_ciphertext,
+        compute_private_log_payload,
     };
     use dep::protocol_types::{
         address::AztecAddress,
@@ -210,13 +224,14 @@ mod test {
             0x25afb798ea6d0b8c1618e50fdeafa463059415013d3b7c75d46abf5e242be70c,
         );
 
-        let log: [u8; 448] = compute_encrypted_log(
+        let log: [u8; 448] = compute_private_log_payload(
             contract_address,
             ovsk_app,
             ovpk_m,
             ivpk_m,
             recipient,
             plaintext,
+            false,
         );
 
         // The following value was generated by `tagged_log.test.ts`