diff --git a/noir-projects/noir-protocol-circuits/crates/types/src/constants.nr b/noir-projects/noir-protocol-circuits/crates/types/src/constants.nr
index 3522de3feae..95dc8666cf2 100644
--- a/noir-projects/noir-protocol-circuits/crates/types/src/constants.nr
+++ b/noir-projects/noir-protocol-circuits/crates/types/src/constants.nr
@@ -189,8 +189,6 @@ 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;
@@ -234,3 +232,8 @@ 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;
diff --git a/yarn-project/circuit-types/src/keys/index.ts b/yarn-project/circuit-types/src/keys/index.ts
index f137b0d567a..c770f679814 100644
--- a/yarn-project/circuit-types/src/keys/index.ts
+++ b/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';
\ No newline at end of file
diff --git a/yarn-project/circuit-types/src/keys/key_store.ts b/yarn-project/circuit-types/src/keys/key_store.ts
index 4869503def4..3cf2c960d59 100644
--- a/yarn-project/circuit-types/src/keys/key_store.ts
+++ b/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 {
   /**
diff --git a/yarn-project/circuit-types/src/keys/new_key_store.ts b/yarn-project/circuit-types/src/keys/new_key_store.ts
new file mode 100644
index 00000000000..861072b8147
--- /dev/null
+++ b/yarn-project/circuit-types/src/keys/new_key_store.ts
@@ -0,0 +1,36 @@
+import { AztecAddress, Fr, PartialAddress, type PublicKey } from '@aztec/circuits.js';
+
+/**
+ * Represents a secure storage for managing keys.
+ */
+export interface NewKeyStore {
+  /**
+   * Retrieves the master nullifier public key.
+   * @returns A Promise that resolves to the master nullifier public key.
+   */
+  getMasterNullifierPublicKey(): Promise<PublicKey>;
+
+  /**
+   * Retrieves the master incoming viewing key.
+   * @returns A Promise that resolves to the master incoming viewing key.
+   */
+  getMasterIncomingViewingPublicKey(): Promise<PublicKey>;
+
+  /**
+   * Retrieves the master outgoing viewing key.
+   * @returns A Promise that resolves to the master outgoing viewing key.
+   */
+  getMasterOutgoingViewingPublicKey(): Promise<PublicKey>;
+
+  /**
+   * Retrieves the master tagging key.
+   * @returns A Promise that resolves to the master tagging key.
+   */
+  getMasterTaggingPublicKey(): Promise<PublicKey>;
+
+  /**
+   * Retrieves the hash of the public keys.
+   * @returns A Promise that resolves to the hash of the public keys.
+   */
+  getPublicKeysHash(): Promise<PublicKey>;
+}
diff --git a/yarn-project/circuits.js/src/constants.gen.ts b/yarn-project/circuits.js/src/constants.gen.ts
index 8879c01216c..2c0c6081456 100644
--- a/yarn-project/circuits.js/src/constants.gen.ts
+++ b/yarn-project/circuits.js/src/constants.gen.ts
@@ -148,4 +148,8 @@ export enum GeneratorIndex {
   FUNCTION_ARGS = 44,
   AUTHWIT_INNER = 45,
   AUTHWIT_OUTER = 46,
+  NSK_M = 47,
+  IVSK_M = 48,
+  OVSK_M = 49,
+  TSK_M = 50,
 }
diff --git a/yarn-project/key-store/src/new_test_key_store.ts b/yarn-project/key-store/src/new_test_key_store.ts
new file mode 100644
index 00000000000..14476d6084b
--- /dev/null
+++ b/yarn-project/key-store/src/new_test_key_store.ts
@@ -0,0 +1,40 @@
+import { type NewKeyStore, type KeyPair, type KeyStore, type PublicKey } from '@aztec/circuit-types';
+import {
+  type AztecAddress,
+  type GrumpkinPrivateKey,
+  GrumpkinScalar,
+  Point,
+  computeNullifierSecretKey,
+  computeSiloedNullifierSecretKey,
+  derivePublicKey,
+  type Fr,
+  GeneratorIndex,
+  Fq,
+} from '@aztec/circuits.js';
+import { type Grumpkin } from '@aztec/circuits.js/barretenberg';
+import { type AztecKVStore, type AztecMap } from '@aztec/kv-store';
+
+import { ConstantKeyPair } from './key_pair.js';
+import { poseidonHash } from '@aztec/foundation/crypto';
+/**
+ * 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: Potentially rename to not include 'Test' in the name.
+ */
+export class NewTestKeyStore implements NewKeyStore {
+  #keys: AztecMap<string, Buffer>;
+
+  constructor(private curve: Grumpkin, database: AztecKVStore) {
+    this.#keys = database.openMap('key_store');
+  }
+
+  public async addAccount(sk: Fr): Promise<PublicKey> {
+    const masterNullifierSecretKey = poseidonHash([sk], GeneratorIndex.NSK_M);
+    // TODO: Is converting from Fr to Fq an issue? Fr.MODULUS is < Fq.MODULUS so it wont' throw but should we refactor this?
+    const masterNullifierPublicKey = this.curve.mul(this.curve.generator(), Fq.fromBuffer(masterNullifierSecretKey.toBuffer()))
+  }
+
+  public async getMasterNullifierPublicKey(): Promise<PublicKey> {
+    return poseidonHash()
+  }
+}
diff --git a/yarn-project/key-store/src/test_key_store.ts b/yarn-project/key-store/src/test_key_store.ts
index a5bfe3144b3..4af7e2c2dfa 100644
--- a/yarn-project/key-store/src/test_key_store.ts
+++ b/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>;