Understanding Metamask: Storing Private Keys and Recovering an EVM Account
Metamask is a popular Ethereum wallet software that allows users to store, manage, and send cryptocurrencies across various blockchain networks. One of its key features is the ability to recover an account from a private key, even if it is locked by a password for a specific machine. In this article, we will delve into the specifics of the Metamask 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. Private keys are encrypted using a specific algorithm that ensures that even if they are compromised, the encryption will be broken and the key cannot be accessed.
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.
Metamask uses the following methods to store private keys:
- Public-Private Key Pair: Private keys are paired with a corresponding public address, allowing users to send/receive cryptocurrencies using the associated address.
- Ethereum Virtual Machine (EVM): When an account is locked with a password for a specific machine, Metamask stores private keys in the EVM, which is used by Ethereum smart contracts. EVM uses private keys to execute transactions and perform calculations.
- Local Storage
: Private keys are stored on the user’s device and are accessible through the Metamask app.
EVM Account Recovery
When an account is recovered from a private key using a machine-specific password, Metamask performs the EVM account recovery process. This includes:
- Private Key Retrieval: 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 in 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.
- Encrypts private keys: To prevent unauthorized access, encrypted private keys are stored in a secure manner using algorithms that make it difficult for attackers to reverse engineer.
Conclusion
Metamask provides robust private key management that allows users to recover accounts from machine-specific passwords. The EVM account recovery process in the wallet ensures the integrity of private keys, even if they are recovered by entering a machine-specific password. 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 required libraries
const { PrivateKey } = require(‘ethereumjs-solidity’);
const { AccountRecoveryOptions } = require(‘@metamask/core’);
// Create a private key from a string (e.g. password)
const privateKey = new PrivateKey(‘your_password_string’);
// Verify a private key against known keys
const knownKeys = [‘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 = wait for eip155.