Add signEIP7702Authorization and corresponding tests to hd and simple Eth keyrings

packages/keyring-eth-hd/src/index.ts

@@ -9,11 +9,13 @@ import {
 import {
   concatSig,
   decrypt,
+  type EIP7702Authorization,
   type EthEncryptedData,
   getEncryptionPublicKey,
   type MessageTypes,
   normalize,
   personalSign,
+  signEIP7702Authorization,
   signTypedData,
   SignTypedDataVersion,
   type TypedDataV1,
@@ -367,6 +369,27 @@ class HdKeyring {
     });
   }
 
+  /**
+   * Sign an EIP-7702 authorization using the private key of the specified account.
+   * This method is compatible with the EIP-7702 standard for enabling smart contract code for EOAs.
+   *
+   * @param withAccount - The address of the account.
+   * @param authorization - The EIP-7702 authorization to sign.
+   * @param opts - The options for selecting the account.
+   * @returns The signature of the authorization.
+   */
+  async signEip7702Authorization(
+    withAccount: Hex,
+    authorization: EIP7702Authorization,
+    opts?: HDKeyringAccountSelectionOptions,
+  ): Promise<string> {
+    const privateKey = this.#getPrivateKeyFor(withAccount, opts);
+    return signEIP7702Authorization({
+      privateKey: Buffer.from(privateKey),
+      authorization,
+    });
+  }
+
   /**
    * Remove an account from the keyring.
    *

packages/keyring-eth-hd/test/index.test.ts

@@ -10,6 +10,7 @@ import * as oldMMForkBIP39 from '@metamask/bip39';
 import {
   normalize,
   personalSign,
+  recoverEIP7702Authorization,
   recoverPersonalSignature,
   recoverTypedSignature,
   signTypedData,
@@ -18,6 +19,7 @@ import {
   type EthEncryptedData,
   type TypedMessage,
   type MessageTypes,
+  type EIP7702Authorization,
 } from '@metamask/eth-sig-util';
 import { wordlist } from '@metamask/scure-bip39/dist/wordlists/english';
 import { assert, type Hex } from '@metamask/utils';
@@ -696,6 +698,62 @@ describe('hd-keyring', () => {
     });
   });
 
+  describe('#signEip7702Authorization', () => {
+    const chainId = 1;
+    const nonce = 1;
+    const contractAddress = '0x1234567890abcdef1234567890abcdef12345678';
+
+    const authorization: EIP7702Authorization = [
+      chainId,
+      contractAddress,
+      nonce,
+    ];
+
+    it('returns the expected value', async () => {
+      const keyring = new HdKeyring();
+      await keyring.deserialize({
+        mnemonic: sampleMnemonic,
+        numberOfAccounts: 1,
+      });
+
+      const signature = await keyring.signEip7702Authorization(
+        firstAcct,
+        authorization,
+      );
+
+      const recovered = recoverEIP7702Authorization({
+        signature,
+        authorization,
+      });
+
+      expect(recovered.toLowerCase()).toStrictEqual(firstAcct.toLowerCase());
+    });
+
+    it('throw an error if an empty address is passed', async () => {
+      const keyring = new HdKeyring();
+      await keyring.deserialize({
+        mnemonic: sampleMnemonic,
+        numberOfAccounts: 1,
+      });
+
+      await expect(
+        keyring.signEip7702Authorization('' as Hex, authorization),
+      ).rejects.toThrow('Must specify address.');
+    });
+
+    it('throw an error if the given address is not associated with the current keyring', async () => {
+      const keyring = new HdKeyring();
+      await keyring.deserialize({
+        mnemonic: sampleMnemonic,
+        numberOfAccounts: 1,
+      });
+
+      await expect(
+        keyring.signEip7702Authorization(notKeyringAddress, authorization),
+      ).rejects.toThrow('HD Keyring - Unable to find matching address.');
+    });
+  });
+
   describe('#removeAccount', function () {
     let keyring: HdKeyring;
     beforeEach(async () => {

packages/keyring-eth-simple/src/simple-keyring.test.ts

@@ -3,15 +3,18 @@ import {
   bufferToHex,
   ecrecover,
   isValidAddress,
+  privateToAddress,
   pubToAddress,
   stripHexPrefix,
   toBuffer,
 } from '@ethereumjs/util';
 import {
+  EIP7702Authorization,
   encrypt,
   getEncryptionPublicKey,
   MessageTypes,
   personalSign,
+  recoverEIP7702Authorization,
   recoverPersonalSignature,
   recoverTypedSignature,
   signTypedData,
@@ -543,6 +546,51 @@ describe('simple-keyring', function () {
     });
   });
 
+  describe('#signEip7702Authorization', function () {
+    const address = '0x29c76e6ad8f28bb1004902578fb108c507be341b';
+    const privKeyHex =
+      '0x4af1bceebf7f3634ec3cff8a2c38e51178d5d4ce585c52d6043e5e2cc3418bb0';
+    const signerAddress = `0x${privateToAddress(
+      Buffer.from(privKeyHex.slice(2), 'hex'),
+    ).toString('hex')}`;
+
+    const chainId = 1;
+    const nonce = 1;
+    const contractAddress = '0x1234567890abcdef1234567890abcdef12345678';
+
+    const authorization: EIP7702Authorization = [
+      chainId,
+      contractAddress,
+      nonce,
+    ];
+
+    it('returns the expected value', async function () {
+      await keyring.deserialize([privKeyHex]);
+      const signature = await keyring.signEip7702Authorization(
+        address,
+        authorization,
+      );
+
+      expect(typeof signature).toBe('string');
+
+      const recovered = recoverEIP7702Authorization({
+        signature,
+        authorization,
+      });
+
+      expect(recovered.toLowerCase()).toStrictEqual(
+        signerAddress.toLowerCase(),
+      );
+    });
+
+    it('throws an error if the address is not in the keyring', async function () {
+      await keyring.deserialize([privKeyHex]);
+      await expect(
+        keyring.signEip7702Authorization(notKeyringAddress, authorization),
+      ).rejects.toThrow('Simple Keyring - Unable to find matching address.');
+    });
+  });
+
   describe('#decryptMessage', function () {
     const address = '0xbe93f9bacbcffc8ee6663f2647917ed7a20a57bb';
     const privateKey = Buffer.from(

packages/keyring-eth-simple/src/simple-keyring.ts

@@ -12,9 +12,11 @@ import {
 import {
   concatSig,
   decrypt,
+  EIP7702Authorization,
   getEncryptionPublicKey,
   normalize,
   personalSign,
+  signEIP7702Authorization,
   signTypedData,
   SignTypedDataVersion,
 } from '@metamask/eth-sig-util';
@@ -96,6 +98,15 @@ export default class SimpleKeyring implements Keyring<string[]> {
     return signedTx ?? transaction;
   }
 
+  async signEip7702Authorization(
+    address: Hex,
+    authorization: EIP7702Authorization,
+    opts: KeyringOpt = {},
+  ): Promise<string> {
+    const privateKey = this.#getPrivateKeyFor(address, opts);
+    return signEIP7702Authorization({ privateKey, authorization });
+  }
+
   // For eth_sign, we need to sign arbitrary data:
   async signMessage(
     address: Hex,