Understanding Metamask: Private Key Storage and EVM Account Recovery

Metamask is a popular Ethereum wallet software that allows users to store, manage, and send cryptocurrencies across different blockchain networks. One of its key features is the ability to recover an account from a private key, even if it is locked with a machine-specific password. In this article, we will dive into the details of Metamask’s private key storage and the EVM account recovery process.

Private Key Storage in Metamask

When a user creates a new wallet or recovers an existing one using their private keys, Metamask stores them securely on the user’s local device. The private keys are encrypted with a specific algorithm, ensuring that even if they are compromised, the encryption will be broken and the key will not be accessible.

Metamask uses a combination of algorithms to store private keys, including:

  • AES-256: A widely used symmetric key block cipher that provides strong encryption.
  • HMAC-SHA-256: A one-way hash function that ensures data integrity.
  • Random Number Generation: Metamask generates a random salt and key for each encrypted private key.

When storing private keys, Metamask uses the following methods:

  • Public-Private Key Pair: Private keys are paired with a corresponding public address, allowing users to send/receive cryptocurrency using the associated address.
  • Ethereum Virtual Machine (EVM): When an account is locked with a machine-specific password, Metamask stores the private keys in the EVM, which is used by Ethereum smart contracts. The EVM uses the private keys to execute transactions and perform computations.
  • Local Storage

    : Private keys are stored on the user’s device, which can be accessed via the Metamask app.

EVM Account Recovery

When an account is recovered from a private key using a machine-specific password, Metamask performs an EVM account recovery process. This involves:

  • Private Key Recovery: The user enters their private key to recover the associated public address.
  • Account Verification: The recovered private key is verified against known private keys stored on the EVM.
  • EVM Account Creation

    : If a valid public address is found, Metamask creates an account using that address and stores it on the Ethereum network.

During this process, Metamask:

  • Encrypts Private Keys: Private keys are encrypted with additional information to ensure their integrity during storage and transmission.
  • Encrypt Private Keys: To prevent unauthorized access, encrypted private keys are stored securely, using algorithms that make it difficult for attackers to reverse engineer them.

Conclusion

Metamask provides robust private key management, allowing users to recover accounts from machine-specific passwords. The wallet’s EVM account recovery process ensures the integrity of private keys, even when they are recovered by entering machine-specific passwords. By understanding how Metamask stores and recovers private keys, users can feel more secure when using their wallets and interacting with smart contracts on the Ethereum network.

Code Example

“`javascript

// Import the required libraries

const { PrivateKey } = require(‘ethereumjs-solidity’);

const { AccountRecoveryOptions } = require(‘@metamask/core’);

// Create a private key from a string (e.g. a password)

const privateKey = new PrivateKey(‘your_password_string’);

// Verify the private key with known keys

constknownKeys = [‘known_key_1’, ‘known_key_2’];

if (!knownKeys.every((key) => privateKey.verify(key))) {

throw new Error(‘Invalid private key’);

}

// Create an account using the recovered private key

const options = new AccountRecoveryOptions();

options.privateKey = privateKey;

accountAddress = await eip155.