BIP39 Passphrase Generator
Generate a BIP39 passphrase (seed) from an existing or random mnemonic phrase. All operations are performed locally in your browser.
BIP39 Mnemonic Generator
Generate secure cryptocurrency seed phrases
Adds extra security. Different passphrases generate different wallets from the same mnemonic.
Security Warning
- • Never share your mnemonic phrase with anyone
- • Store it securely offline (paper, metal backup)
- • Anyone with your mnemonic can access your funds
- • This tool runs entirely in your browser - no data is sent to servers
BIP39 (Bitcoin Improvement Proposal 39) defines a standard for generating mnemonic phrases that can be used to derive cryptocurrency wallet keys. The mnemonic is converted to a 512-bit seed using PBKDF2 with 2048 iterations.
About BIP39
BIP39 (Bitcoin Improvement Proposal 39) is a standard for creating mnemonic phrases that can be used to generate deterministic wallets. It provides a way to create human-readable backup phrases for cryptographic keys.
Key features of BIP39:
- Human-readable: Uses common words for easy backup and recovery
- Deterministic: Same mnemonic always generates the same seed
- Multi-language: Supports multiple languages for word lists
- Checksum: Includes error detection to prevent typos
BIP39 Structure
A BIP39 mnemonic consists of:
Mnemonic = [Entropy] + [Checksum]
| Word Count | Entropy (bits) | Checksum (bits) | Total (bits) |
|---|---|---|---|
| 12 words | 128 | 4 | 132 |
| 15 words | 160 | 5 | 165 |
| 18 words | 192 | 6 | 198 |
| 21 words | 224 | 7 | 231 |
| 24 words | 256 | 8 | 264 |
BIP39 Implementation in Different Languages
JavaScript:
import * as bip39 from 'bip39';
// Generate a random mnemonic
const mnemonic = bip39.generateMnemonic();
// Example: 'abandon abandon abandon abandon abandon abandon abandon abandon about'
// Convert mnemonic to seed
const seed = bip39.mnemonicToSeedSync(mnemonic);
Python:
from mnemonic import Mnemonic
# Generate a random mnemonic
mnemo = Mnemonic("english")
mnemonic = mnemo.generate()
# Example: 'abandon abandon abandon abandon abandon abandon abandon abandon about'
# Convert mnemonic to seed
seed = mnemo.to_seed(mnemonic)
Common BIP39 Use Cases
- Cryptocurrency Wallets - Generate and backup wallet seeds
- Key Derivation - Create multiple keys from a single seed
- Secure Backup - Create human-readable backups of cryptographic keys
- Multi-account Systems - Generate multiple accounts from a single seed
- Password Generation - Create secure, memorable passwords