refactor: replace token note with uint note (#8143)

In this PR, we are replacing the token note with our previously added
U128 note and making BalanceSet hold a UintNote instead of being
generic. The token note is now redundant as we have a UintNote in aztec
nr now.

Resolves #8107.

docs/docs/aztec/concepts/storage/partial_notes.md

@@ -68,8 +68,8 @@ Now let's do the same for partial notes.
 
 ## Partial notes life cycle
 
-1. Create a partial/unfinished note in a private function of your contract --> partial here means that the values within the note are not yet considered finalized (e.g. `amount` in a `TokenNote`),
-2. compute a note hiding point of the partial note using a multi scalar multiplication on an elliptic curve. For `TokenNote` this would be done as `G_amt * amount0 + G_npk * npk_m_hash + G_rnd * randomness + G_slot * slot`, where each `G_` is a generator point for a specific field in the note,
+1. Create a partial/unfinished note in a private function of your contract --> partial here means that the values within the note are not yet considered finalized (e.g. `amount` in a `UintNote`),
+2. compute a note hiding point of the partial note using a multi scalar multiplication on an elliptic curve. For `UintNote` this would be done as `G_amt * amount0 + G_npk * npk_m_hash + G_rnd * randomness + G_slot * slot`, where each `G_` is a generator point for a specific field in the note,
 3. emit partial note log,
 4. pass the note hiding point to a public function,
 5. in a public function determine the value you want to add to the note (e.g. adding a value to an amount) and add it to the note hiding point (e.g. `NOTE_HIDING_POINT + G_amt * amount`),
@@ -136,7 +136,7 @@ Then we just emit `P_a.x` and `P_b.x` as a note hashes, and we're done!
 
 This is implemented by applying the `partial_note` attribute:
 
-#include_code TokenNote noir-projects/noir-contracts/contracts/token_contract/src/types/token_note.nr rust
+#include_code UintNote noir-projects/aztec-nr/uint-note/src/uint_note.nr rust
 
 Those `G_x` are generators that generated [here](https://github.com/AztecProtocol/aztec-packages/blob/#include_aztec_version/noir-projects/noir-projects/aztec-nr/aztec/src/generators.nr). Anyone can use them for separating different fields in a "partial note".
 

docs/docs/guides/developer_guides/smart_contracts/how_to_compile_contract.md

@@ -146,7 +146,7 @@ export class TokenContract extends ContractBase {
       },
       balances: {
         slot: new Fr(3n),
-        typ: 'BalancesMap<TokenNote>',
+        typ: 'BalancesMap',
       },
       total_supply: {
         slot: new Fr(4n),
@@ -185,16 +185,16 @@ export class TokenContract extends ContractBase {
     >;
   }
 
-  public static get notes(): ContractNotes<'TransparentNote' | 'TokenNote'> {
+  public static get notes(): ContractNotes<'TransparentNote' | 'UintNote'> {
     const notes = this.artifact.outputs.globals.notes ? (this.artifact.outputs.globals.notes as any) : [];
     return {
       TransparentNote: {
         id: new Fr(84114971101151129711410111011678111116101n),
       },
-      TokenNote: {
+      UintNote: {
         id: new Fr(8411110710111078111116101n),
       },
-    } as ContractNotes<'TransparentNote' | 'TokenNote'>;
+    } as ContractNotes<'TransparentNote' | 'UintNote'>;
   }
 
   /** Type-safe wrappers for the public methods exposed by the contract. */

docs/docs/guides/developer_guides/smart_contracts/writing_contracts/storage/storage_slots.md

@@ -27,12 +27,12 @@ sequenceDiagram
     BalanceMap->>BalanceMap: derived_slot = H(map_slot, to)
     BalanceMap->>BalanceSet: BalanceSet::new(to, derived_slot)
     Token->>BalanceSet: to_bal.add(amount)
-    BalanceSet->>BalanceSet: note = TokenNote::new(amount, to)
+    BalanceSet->>BalanceSet: note = UintNote::new(amount, to)
     BalanceSet->>Set: insert(note)
     Set->>LifeCycle: create_note(derived_slot, note)
     LifeCycle->>LifeCycle: note.header = NoteHeader { contract_address, <br> storage_slot: derived_slot, nonce: 0, note_hash_counter }
-    Utils->>TokenNote: note_hiding_point = note.compute_note_hiding_point()
-    TokenNote->>Utils: note_hash = note_hiding_point.x
+    Utils->>UintNote: note_hiding_point = note.compute_note_hiding_point()
+    UintNote->>Utils: note_hash = note_hiding_point.x
     LifeCycle->>Context: push_note_hash(note_hash)
     end
     Context->>Kernel: unique_note_hash = H(nonce, note_hash)

docs/docs/tutorials/codealong/contract_tutorials/token_contract.md

@@ -52,7 +52,7 @@ compressed_string = {git="https://github.com/AztecProtocol/aztec-packages/", tag
 
 We will be working within `main.nr` for the rest of the tutorial.
 
-## How this will work 
+## How this will work
 
 Before writing the functions, let's go through them to see how this contract will work:
 
@@ -158,7 +158,7 @@ Reading through the storage variables:
 
 - `admin` an Aztec address stored in public state.
 - `minters` is a mapping of Aztec addresses in public state. This will store whether an account is an approved minter on the contract.
-- `balances` is a mapping of private balances. Private balances are stored in a `PrivateSet` of `TokenNote`s. The balance is the sum of all of an account's `TokenNote`s.
+- `balances` is a mapping of private balances. Private balances are stored in a `PrivateSet` of `UintNote`s. The balance is the sum of all of an account's `UintNote`s.
 - `total_supply` is an unsigned integer (max 128 bit value) stored in public state and represents the total number of tokens minted.
 - `pending_shields` is a `PrivateSet` of `TransparentNote`s stored in private state. What is stored publicly is a set of commitments to `TransparentNote`s.
 - `public_balances` is a mapping of Aztec addresses in public state and represents the publicly viewable balances of accounts.
@@ -257,7 +257,7 @@ Storage is referenced as `storage.variable`.
 
 #### `redeem_shield`
 
-This private function enables an account to move tokens from a `TransparentNote` in the `pending_shields` mapping to a `TokenNote` in private `balances`. The `TokenNote` will be associated with a nullifier key, so any account that knows this key can spend this note.
+This private function enables an account to move tokens from a `TransparentNote` in the `pending_shields` mapping to a `UintNote` in private `balances`. The `UintNote` will be associated with a nullifier key, so any account that knows this key can spend this note.
 
 Going through the function logic, first the `secret_hash` is generated from the given secret. This ensures that only the entity possessing the secret can use it to redeem the note. Following this, a `TransparentNote` is retrieved from the set, using the provided amount and secret. The note is subsequently removed from the set, allowing it to be redeemed only once. The recipient's private balance is then increased using the `increment` helper function from the `value_note` [library (GitHub link)](https://github.com/AztecProtocol/aztec-packages/blob/#include_aztec_version/noir-projects/aztec-nr/value-note/src/utils.nr).
 
@@ -267,7 +267,7 @@ The function returns `1` to indicate successful execution.
 
 #### `unshield`
 
-This private function enables un-shielding of private `TokenNote`s stored in `balances` to any Aztec account's `public_balance`.
+This private function enables un-shielding of private `UintNote`s stored in `balances` to any Aztec account's `public_balance`.
 
 After initializing storage, the function checks that the `msg_sender` is authorized to spend tokens. See [the Authorizing token spends section](#authorizing-token-spends) above for more detail--the only difference being that `assert_valid_message_for` is modified to work specifically in the private context. After the authorization check, the sender's private balance is decreased using the `decrement` helper function for the `value_note` library. Then it stages a public function call on this contract ([`_increase_public_balance`](#_increase_public_balance)) to be executed in the [public execution phase](#execution-contexts) of transaction execution. `_increase_public_balance` is marked as an `internal` function, so can only be called by this token contract.
 

noir-projects/aztec-nr/uint-note/src/uint_note.nr

@@ -1,24 +1,28 @@
 use dep::aztec::{
     keys::getters::get_nsk_app,
-    macros::notes::note,
+    macros::notes::partial_note,
     note::utils::compute_note_hash_for_nullify,
-    prelude::{NullifiableNote, PrivateContext},
+    oracle::random::random,
+    prelude::{NoteHeader, NullifiableNote, PrivateContext},
     protocol_types::{
         constants::GENERATOR_INDEX__NOTE_NULLIFIER, hash::poseidon2_hash_with_separator,
     },
 };
 
-#[note]
+// docs:start:UintNote
+#[partial_note(quote {value})]
 pub struct UintNote {
-    // The integer stored by the note
+    // The amount of tokens in the note
     value: U128,
     // The nullifying public key hash is used with the nsk_app to ensure that the note can be privately spent.
     npk_m_hash: Field,
     // Randomness of the note to hide its contents
     randomness: Field,
 }
+// docs:end:UintNote
 
 impl NullifiableNote for UintNote {
+    // docs:start:nullifier
     fn compute_nullifier(
         self,
         context: &mut PrivateContext,
@@ -30,6 +34,7 @@ impl NullifiableNote for UintNote {
             GENERATOR_INDEX__NOTE_NULLIFIER as Field,
         )
     }
+    // docs:end:nullifier
 
     unconstrained fn compute_nullifier_without_context(self) -> Field {
         let note_hash_for_nullify = compute_note_hash_for_nullify(self);
@@ -48,3 +53,18 @@ impl Eq for UintNote {
             & (self.randomness == other.randomness)
     }
 }
+
+impl UintNote {
+    pub fn new(value: U128, owner_npk_m_hash: Field) -> Self {
+        // We use the randomness to preserve the privacy of the note recipient by preventing brute-forcing, so a
+        // malicious sender could use non-random values to make the note less private. But they already know the full
+        // note pre-image anyway, and so the recipient already trusts them to not disclose this information. We can
+        // therefore assume that the sender will cooperate in the random value generation.
+        let randomness = unsafe { random() };
+        Self { value, npk_m_hash: owner_npk_m_hash, randomness, header: NoteHeader::empty() }
+    }
+
+    pub fn get_value(self) -> U128 {
+        self.value
+    }
+}

noir-projects/noir-contracts/contracts/token_blacklist_contract/src/main.nr

@@ -14,9 +14,7 @@ use dep::aztec::macros::aztec;
 contract TokenBlacklist {
     // Libs
     use dep::aztec::{
-        encrypted_logs::encrypted_note_emission::{
-            encode_and_encrypt_note, encode_and_encrypt_note_unconstrained,
-        },
+        encrypted_logs::encrypted_note_emission::encode_and_encrypt_note_unconstrained,
         hash::compute_secret_hash,
         keys::getters::get_public_keys,
         macros::{functions::{initializer, internal, private, public, view}, storage::storage},

noir-projects/noir-contracts/contracts/token_contract/Nargo.toml

@@ -6,5 +6,6 @@ type = "contract"
 
 [dependencies]
 aztec = { path = "../../../aztec-nr/aztec" }
+uint_note = { path = "../../../aztec-nr/uint-note" }
 compressed_string = { path = "../../../aztec-nr/compressed-string" }
 authwit = { path = "../../../aztec-nr/authwit" }

noir-projects/noir-contracts/contracts/token_contract/src/main.nr

@@ -42,16 +42,16 @@ contract Token {
         utils::comparison::Comparator,
     };
 
+    use dep::uint_note::uint_note::UintNote;
+
     // docs:start:import_authwit
     use dep::authwit::auth::{
         assert_current_call_valid_authwit, assert_current_call_valid_authwit_public,
         compute_authwit_nullifier,
     };
     // docs:end:import_authwit
 
-    use crate::types::{
-        balance_set::BalanceSet, token_note::TokenNote, transparent_note::TransparentNote,
-    };
+    use crate::types::{balance_set::BalanceSet, transparent_note::TransparentNote};
 
     // docs:end::imports
 
@@ -82,7 +82,7 @@ contract Token {
         minters: Map<AztecAddress, PublicMutable<bool, Context>, Context>,
         // docs:end:storage_minters
         // docs:start:storage_balances
-        balances: Map<AztecAddress, BalanceSet<TokenNote, Context>, Context>,
+        balances: Map<AztecAddress, BalanceSet<Context>, Context>,
         // docs:end:storage_balances
         total_supply: PublicMutable<U128, Context>,
         // docs:start:storage_pending_shields
@@ -571,13 +571,13 @@ contract Token {
         let fee_payer_randomness = unsafe { random() };
         let user_randomness = unsafe { random() };
 
-        let fee_payer_setup_payload = TokenNote::setup_payload().new(
+        let fee_payer_setup_payload = UintNote::setup_payload().new(
             fee_payer_npk_m_hash,
             fee_payer_randomness,
             storage.balances.at(fee_payer).set.storage_slot,
         );
 
-        let user_setup_payload = TokenNote::setup_payload().new(
+        let user_setup_payload = UintNote::setup_payload().new(
             user_npk_m_hash,
             user_randomness,
             storage.balances.at(user).set.storage_slot,
@@ -665,9 +665,9 @@ contract Token {
         // 3. We construct the note finalization payloads with the correct amounts and hiding points to get the note
         // hashes and unencrypted logs.
         let fee_payer_finalization_payload =
-            TokenNote::finalization_payload().new(&mut context, fee_payer_slot, tx_fee);
+            UintNote::finalization_payload().new(&mut context, fee_payer_slot, tx_fee);
         let user_finalization_payload =
-            TokenNote::finalization_payload().new(&mut context, user_slot, refund_amount);
+            UintNote::finalization_payload().new(&mut context, user_slot, refund_amount);
 
         // 4. At last we emit the note hashes and the final note logs.
         fee_payer_finalization_payload.emit();

noir-projects/noir-contracts/contracts/token_contract/src/test/refunds.nr

@@ -1,10 +1,11 @@
-use crate::{test::utils, Token, types::token_note::TokenNote};
+use crate::{test::utils, Token};
 
 use dep::authwit::cheatcodes as authwit_cheatcodes;
 use dep::aztec::{
     keys::getters::get_public_keys, prelude::NoteHeader,
     protocol_types::storage::map::derive_storage_slot_in_map,
 };
+use dep::uint_note::uint_note::UintNote;
 use std::test::OracleMock;
 
 #[test]
@@ -48,8 +49,8 @@ unconstrained fn setup_refund_success() {
     // worth  `funded_amount - transaction_fee`. We "know" the transaction fee was 1 (it is hardcoded in
     // `executePublicFunction` TXE oracle) but we need to notify TXE of the note (preimage).
     env.add_note(
-        &mut TokenNote {
-            amount: U128::from_integer(funded_amount - 1),
+        &mut UintNote {
+            value: U128::from_integer(funded_amount - 1),
             npk_m_hash: user_npk_m_hash,
             randomness: user_randomness,
             header: NoteHeader::empty(),
@@ -58,8 +59,8 @@ unconstrained fn setup_refund_success() {
         token_contract_address,
     );
     env.add_note(
-        &mut TokenNote {
-            amount: U128::from_integer(1),
+        &mut UintNote {
+            value: U128::from_integer(1),
             npk_m_hash: fee_payer_npk_m_hash,
             randomness: fee_payer_randomness,
             header: NoteHeader::empty(),

noir-projects/noir-contracts/contracts/token_contract/src/types.nr

@@ -1,3 +1,2 @@
 mod transparent_note;
 mod balance_set;
-mod token_note;