Ethereum Address Generation: A Practical Guide

Understanding Ethereum Addresses

Ethereum addresses serve as unique identifiers on the Ethereum network, enabling users to:

• Send and receive ETH
• Interact with smart contracts
• Execute transactions

Key Characteristics

Format and Length

• 42-character hexadecimal string
• Prefix: 0x (indicating hexadecimal format)
• Followed by 40 alphanumeric characters (0-9, a-f)
• Example: 0x742d35Cc6634C0532925a3b844Bc454e4438f44e

Generation Process

1. Public Key Derivation: Created using Elliptic Curve Digital Signature Algorithm (ECDSA)
2. Hashing: Processed through Keccak-256 hash function
3. Truncation: Last 20 bytes become the final address

Case Insensitivity

Ethereum addresses are case-insensitive in comparisons:

• 0xABC... ≡ 0xabc...
• Mixed-case versions exist for checksum verification

Technical Clarifications

Character vs Byte Representation

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Step-by-Step Address Generation

1. Private Key Creation

• 256-bit random number (64 hex characters)
• Example: 0x56f7...f51e

2. Public Key Generation

• Using secp256k1 ECDSA curve
• 65-byte uncompressed format (130 hex chars)
• Prefix: 0x04

3. Address Derivation

1. Remove 0x04 prefix
2. Apply Keccak-256 hashing
3. Extract last 20 bytes

4. Address Formatting

• Add 0x prefix
• 40-character hexadecimal string

5. Checksum Implementation (Optional)

• EIP-55 standard mixed-case formatting
• Example: 0x5aAeb...BeAed

BIP32/BIP39 Standard Implementation

Using EthereumJS Wallet Library

import { hdkey } from '@ethereumjs/wallet';

function createEthAddress(seedHex: string, addressIndex: string) {
  const path = `m/44'/60'/0'/0/${addressIndex}`;
  const hdNode = hdkey.EthereumHDKey.fromMasterSeed(Buffer.from(seedHex, 'hex'));
  const wallet = hdNode.derivePath(path).getWallet();
  
  return {
    privateKey: wallet.getPrivateKeyString(),
    publicKey: wallet.getPublicKeyString(),
    address: wallet.getAddressString()
  };
}

Practical Example

const mnemonic = 'lounge face pattern cinnamon shrug average spend...';
const seed = bip39.mnemonicToSeedSync(mnemonic);
const account = createEthAddress(seed.toString('hex'), '0');

console.log('Address:', account.address); // 0x349a...c52e

Security Best Practices

1. Always generate private keys in secure environments
2. Use hardware wallets for significant holdings
3. Verify checksum addresses when possible
4. Never share private keys or recovery phrases

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Frequently Asked Questions

1. Can two people generate the same Ethereum address?

Statistically impossible due to 2^160 possible address combinations - more than atoms in the observable universe.

2. Are Ethereum addresses case-sensitive?

For transaction purposes: no. Checksum addresses use mixed case for error detection only.

3. How are ERC-20 token addresses different?

They use the same format but represent smart contract locations rather than EOA (Externally Owned Accounts).

4. What happens if I lose my private key?

Without backups or recovery phrases, funds become permanently inaccessible due to Ethereum's decentralized nature.

5. Why does MetaMask show different addresses?

Wallet software generates new addresses from the same seed using derivation paths - all valid and controlled by your seed phrase.

6. Can I customize my Ethereum address?

Possible through "vanity address" generators, but requires significant computation for longer custom patterns.