feat: new key store (#5653)

Fixes #5607

noir-projects/noir-protocol-circuits/crates/types/src/constants.nr

@@ -193,8 +193,6 @@ global NUM_BASE_PARITY_PER_ROOT_PARITY: u64 = 4;
  * | MID       | 8 < n ≤ 16                    | 32 < hash_index ≤ 40 |
  * | HIGH      | 16 < n ≤ 48                   | 40 < hash_index ≤ 48 |
  * +-----------+-------------------------------+----------------------+
- *
- * Note: When modifying, modify `GeneratorIndexPacker` in packer.hpp accordingly.
  */
 // Indices with size ≤ 8
 global GENERATOR_INDEX__NOTE_HASH = 1;
@@ -238,3 +236,10 @@ global GENERATOR_INDEX__PUBLIC_CIRCUIT_PUBLIC_INPUTS = 43;
 global GENERATOR_INDEX__FUNCTION_ARGS = 44;
 global GENERATOR_INDEX__AUTHWIT_INNER = 45;
 global GENERATOR_INDEX__AUTHWIT_OUTER = 46;
+// Key related generators follow
+global GENERATOR_INDEX__NSK_M = 47;
+global GENERATOR_INDEX__IVSK_M = 48;
+global GENERATOR_INDEX__OVSK_M = 49;
+global GENERATOR_INDEX__TSK_M = 50;
+global GENERATOR_INDEX__PUBLIC_KEYS_HASH = 51;
+global GENERATOR_INDEX__CONTRACT_ADDRESS_V1 = 52;

yarn-project/circuit-types/src/keys/index.ts

@@ -1,2 +1,3 @@
 export * from './key_pair.js';
 export * from './key_store.js';
+export * from './new_key_store.js';

yarn-project/circuit-types/src/keys/key_store.ts

@@ -3,6 +3,7 @@ import { type AztecAddress, type GrumpkinPrivateKey, type PublicKey } from '@azt
 /**
  * Represents a secure storage for managing keys.
  * Provides functionality to create and retrieve accounts, private and public keys,
+ * TODO(#5627): 💣💣💣
  */
 export interface KeyStore {
   /**

yarn-project/circuit-types/src/keys/new_key_store.ts

@@ -0,0 +1,52 @@
+import { type AztecAddress, type Fr, type PartialAddress, type PublicKey } from '@aztec/circuits.js';
+
+/**
+ * Represents a secure storage for managing keys.
+ */
+export interface NewKeyStore {
+  /**
+   * Creates a new account from a randomly generated secret key.
+   * @returns A promise that resolves to the newly created account's AztecAddress.
+   */
+  createAccount(): Promise<AztecAddress>;
+
+  /**
+   * Adds an account to the key store from the provided secret key.
+   * @param sk - The secret key of the account.
+   * @param partialAddress - The partial address of the account.
+   * @returns The account's address.
+   */
+  addAccount(sk: Fr, partialAddress: PartialAddress): Promise<AztecAddress>;
+
+  /**
+   * Gets the master nullifier public key for a given account.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account address for which to retrieve the master nullifier public key.
+   * @returns The master nullifier public key for the account.
+   */
+  getMasterNullifierPublicKey(account: AztecAddress): Promise<PublicKey>;
+
+  /**
+   * Gets the master incoming viewing public key for a given account.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account address for which to retrieve the master incoming viewing public key.
+   * @returns The master incoming viewing public key for the account.
+   */
+  getMasterIncomingViewingPublicKey(account: AztecAddress): Promise<PublicKey>;
+
+  /**
+   * Retrieves the master outgoing viewing key.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account to retrieve the master outgoing viewing key for.
+   * @returns A Promise that resolves to the master outgoing viewing key.
+   */
+  getMasterOutgoingViewingPublicKey(account: AztecAddress): Promise<PublicKey>;
+
+  /**
+   * Retrieves the master tagging key.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account to retrieve the master tagging key for.
+   * @returns A Promise that resolves to the master tagging key.
+   */
+  getMasterTaggingPublicKey(account: AztecAddress): Promise<PublicKey>;
+}

yarn-project/circuits.js/src/constants.gen.ts

@@ -152,4 +152,10 @@ export enum GeneratorIndex {
   FUNCTION_ARGS = 44,
   AUTHWIT_INNER = 45,
   AUTHWIT_OUTER = 46,
+  NSK_M = 47,
+  IVSK_M = 48,
+  OVSK_M = 49,
+  TSK_M = 50,
+  PUBLIC_KEYS_HASH = 51,
+  CONTRACT_ADDRESS_V1 = 52,
 }

yarn-project/foundation/src/crypto/index.ts

@@ -3,6 +3,7 @@ import { BarretenbergSync } from '@aztec/bb.js';
 export * from './keccak/index.js';
 export * from './random/index.js';
 export * from './sha256/index.js';
+export * from './sha512/index.js';
 export * from './pedersen/index.js';
 export * from './poseidon/index.js';
 

yarn-project/foundation/src/crypto/sha512/index.ts

@@ -0,0 +1,16 @@
+import { default as hash } from 'hash.js';
+
+import { GrumpkinScalar } from '../../fields/fields.js';
+import { type Bufferable, serializeToBuffer } from '../../serialize/serialize.js';
+
+export const sha512 = (data: Buffer) => Buffer.from(hash.sha512().update(data).digest());
+
+/**
+ * @dev We don't truncate in this function (unlike in sha256ToField) because this function is used in situations where
+ * we don't care only about collision resistance but we need the output to be uniformly distributed as well. This is
+ * because we use it as a pseudo-random function.
+ */
+export const sha512ToGrumpkinScalar = (data: Bufferable[]) => {
+  const buffer = serializeToBuffer(data);
+  return GrumpkinScalar.fromBufferReduce(sha512(buffer));
+};

yarn-project/key-store/src/new_test_key_store.test.ts

@@ -0,0 +1,42 @@
+import { Fr } from '@aztec/circuits.js';
+import { Grumpkin } from '@aztec/circuits.js/barretenberg';
+import { openTmpStore } from '@aztec/kv-store/utils';
+
+import { NewTestKeyStore } from './new_test_key_store.js';
+
+describe('NewTestKeyStore', () => {
+  it('Adds account and returns keys', async () => {
+    const db = openTmpStore();
+    const keyStore = new NewTestKeyStore(new Grumpkin(), db);
+
+    // Arbitrary fixed values
+    const sk = new Fr(8923n);
+    const partialAddress = new Fr(243523n);
+
+    const accountAddress = await keyStore.addAccount(sk, partialAddress);
+    expect(accountAddress.toString()).toMatchInlineSnapshot(
+      `"0x2e34847ad9019320ac89a6ec9b42fec90f94ef4162fdfdd7f5b7668e32d82655"`,
+    );
+
+    // TODO(#5714): The keys are currently the same here because separator is currently ignored in poseidon
+    const masterNullifierPublicKey = await keyStore.getMasterNullifierPublicKey(accountAddress);
+    expect(masterNullifierPublicKey.toString()).toMatchInlineSnapshot(
+      `"0x2ef5d15dd65d29546680ab72846fb071f41cb9f2a0212215e6c560e29df4ff650ce764818364b376be92dc2f49577fe440e64a16012584f7c4ee94f7edbc323a"`,
+    );
+
+    const masterIncomingViewingPublicKey = await keyStore.getMasterIncomingViewingPublicKey(accountAddress);
+    expect(masterIncomingViewingPublicKey.toString()).toMatchInlineSnapshot(
+      `"0x1c088f4e4a711f236a88b55da9ddf388de0bc00d56a5ceca96cea3a5cbe75bf32db0a333ba30c36b844d9fc6d2fb0de8d10e4371f0c5baebae452d90ff366798"`,
+    );
+
+    const masterOutgoingViewingPublicKey = await keyStore.getMasterOutgoingViewingPublicKey(accountAddress);
+    expect(masterOutgoingViewingPublicKey.toString()).toMatchInlineSnapshot(
+      `"0x232d0b445d097fbc2046012c3fc474f6a9beef97eda1d8d1f2487dbe501ee1e70e8db9a824531a14e8717dee54cbb7abfec29a88c550a49617258bd6fd858242"`,
+    );
+
+    const masterTaggingPublicKey = await keyStore.getMasterTaggingPublicKey(accountAddress);
+    expect(masterTaggingPublicKey.toString()).toMatchInlineSnapshot(
+      `"0x076429010fdebfa522b053267f654a4c5daf18589915d96f7e5001d63ea2033f27f915f254560c84450aa38e93c3162be52492d05b316e75f542e3b302117360"`,
+    );
+  });
+});

yarn-project/key-store/src/new_test_key_store.ts

@@ -0,0 +1,130 @@
+import { type NewKeyStore, type PublicKey } from '@aztec/circuit-types';
+import { AztecAddress, Fr, GeneratorIndex, type PartialAddress, Point } from '@aztec/circuits.js';
+import { type Grumpkin } from '@aztec/circuits.js/barretenberg';
+import { poseidon2Hash, sha512ToGrumpkinScalar } from '@aztec/foundation/crypto';
+import { type AztecKVStore, type AztecMap } from '@aztec/kv-store';
+
+/**
+ * TestKeyStore is an implementation of the KeyStore interface, used for managing key pairs in a testing environment.
+ * It should be utilized in testing scenarios where secure key management is not required, and ease-of-use is prioritized.
+ */
+export class NewTestKeyStore implements NewKeyStore {
+  #keys: AztecMap<string, Buffer>;
+
+  constructor(private curve: Grumpkin, database: AztecKVStore) {
+    this.#keys = database.openMap('key_store');
+  }
+
+  /**
+   * Creates a new account from a randomly generated secret key.
+   * @returns A promise that resolves to the newly created account's AztecAddress.
+   */
+  public createAccount(): Promise<AztecAddress> {
+    const sk = Fr.random();
+    const partialAddress = Fr.random();
+    return this.addAccount(sk, partialAddress);
+  }
+
+  /**
+   * Adds an account to the key store from the provided secret key.
+   * @param sk - The secret key of the account.
+   * @param partialAddress - The partial address of the account.
+   * @returns The account's address.
+   */
+  public async addAccount(sk: Fr, partialAddress: PartialAddress): Promise<AztecAddress> {
+    // First we derive master secret keys -  we use sha512 here because this derivation will never take place
+    // in a circuit
+    const masterNullifierSecretKey = sha512ToGrumpkinScalar([sk, GeneratorIndex.NSK_M]);
+    const masterIncomingViewingSecretKey = sha512ToGrumpkinScalar([sk, GeneratorIndex.IVSK_M]);
+    const masterOutgoingViewingSecretKey = sha512ToGrumpkinScalar([sk, GeneratorIndex.OVSK_M]);
+    const masterTaggingSecretKey = sha512ToGrumpkinScalar([sk, GeneratorIndex.TSK_M]);
+
+    // Then we derive master public keys
+    const masterNullifierPublicKey = this.curve.mul(this.curve.generator(), masterNullifierSecretKey);
+    const masterIncomingViewingPublicKey = this.curve.mul(this.curve.generator(), masterIncomingViewingSecretKey);
+    const masterOutgoingViewingPublicKey = this.curve.mul(this.curve.generator(), masterOutgoingViewingSecretKey);
+    const masterTaggingPublicKey = this.curve.mul(this.curve.generator(), masterTaggingSecretKey);
+
+    // We hash the public keys to get the public keys hash
+    const publicKeysHash = poseidon2Hash(
+      [
+        masterNullifierPublicKey,
+        masterIncomingViewingPublicKey,
+        masterOutgoingViewingPublicKey,
+        masterTaggingPublicKey,
+      ],
+      GeneratorIndex.PUBLIC_KEYS_HASH,
+    );
+
+    // We hash the partial address and the public keys hash to get the account address
+    // TODO(#5726): Should GeneratorIndex.CONTRACT_ADDRESS be removed given that we introduced CONTRACT_ADDRESS_V1?
+    // TODO(#5726): Move the following line to AztecAddress class?
+    const accountAddressFr = poseidon2Hash([partialAddress, publicKeysHash], GeneratorIndex.CONTRACT_ADDRESS_V1);
+    const accountAddress = AztecAddress.fromField(accountAddressFr);
+
+    // We store the keys in the database
+    await this.#keys.set(`${accountAddress.toString()}-npk_m`, masterNullifierPublicKey.toBuffer());
+    await this.#keys.set(`${accountAddress.toString()}-ivpk_m`, masterIncomingViewingPublicKey.toBuffer());
+    await this.#keys.set(`${accountAddress.toString()}-ovpk_m`, masterOutgoingViewingPublicKey.toBuffer());
+    await this.#keys.set(`${accountAddress.toString()}-tpk_m`, masterTaggingPublicKey.toBuffer());
+
+    // At last, we return the newly derived account address
+    return Promise.resolve(accountAddress);
+  }
+
+  /**
+   * Gets the master nullifier public key for a given account.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account address for which to retrieve the master nullifier public key.
+   * @returns The master nullifier public key for the account.
+   */
+  public getMasterNullifierPublicKey(account: AztecAddress): Promise<PublicKey> {
+    const masterNullifierPublicKeyBuffer = this.#keys.get(`${account.toString()}-npk_m`);
+    if (!masterNullifierPublicKeyBuffer) {
+      throw new Error(`Account ${account.toString()} does not exist.`);
+    }
+    return Promise.resolve(Point.fromBuffer(masterNullifierPublicKeyBuffer));
+  }
+
+  /**
+   * Gets the master incoming viewing public key for a given account.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account address for which to retrieve the master incoming viewing public key.
+   * @returns The master incoming viewing public key for the account.
+   */
+  public getMasterIncomingViewingPublicKey(account: AztecAddress): Promise<PublicKey> {
+    const masterIncomingViewingPublicKeyBuffer = this.#keys.get(`${account.toString()}-ivpk_m`);
+    if (!masterIncomingViewingPublicKeyBuffer) {
+      throw new Error(`Account ${account.toString()} does not exist.`);
+    }
+    return Promise.resolve(Point.fromBuffer(masterIncomingViewingPublicKeyBuffer));
+  }
+
+  /**
+   * Retrieves the master outgoing viewing public key.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account to retrieve the master outgoing viewing key for.
+   * @returns A Promise that resolves to the master outgoing viewing key.
+   */
+  public getMasterOutgoingViewingPublicKey(account: AztecAddress): Promise<PublicKey> {
+    const masterOutgoingViewingPublicKeyBuffer = this.#keys.get(`${account.toString()}-ovpk_m`);
+    if (!masterOutgoingViewingPublicKeyBuffer) {
+      throw new Error(`Account ${account.toString()} does not exist.`);
+    }
+    return Promise.resolve(Point.fromBuffer(masterOutgoingViewingPublicKeyBuffer));
+  }
+
+  /**
+   * Retrieves the master tagging public key.
+   * @throws If the account does not exist in the key store.
+   * @param account - The account to retrieve the master tagging key for.
+   * @returns A Promise that resolves to the master tagging key.
+   */
+  public getMasterTaggingPublicKey(account: AztecAddress): Promise<PublicKey> {
+    const masterTaggingPublicKeyBuffer = this.#keys.get(`${account.toString()}-tpk_m`);
+    if (!masterTaggingPublicKeyBuffer) {
+      throw new Error(`Account ${account.toString()} does not exist.`);
+    }
+    return Promise.resolve(Point.fromBuffer(masterTaggingPublicKeyBuffer));
+  }
+}

yarn-project/key-store/src/test_key_store.ts

@@ -16,6 +16,7 @@ import { ConstantKeyPair } from './key_pair.js';
 /**
  * TestKeyStore is an implementation of the KeyStore interface, used for managing key pairs in a testing environment.
  * It should be utilized in testing scenarios where secure key management is not required, and ease-of-use is prioritized.
+ * TODO(#5627): 💣💣💣
  */
 export class TestKeyStore implements KeyStore {
   #keys: AztecMap<string, Buffer>;