BIP39 Passphrase Generator
Generate a BIP39 passphrase (seed) from an existing or random mnemonic phrase. All operations are performed locally in your browser.
Enter a BIP39 mnemonic phrase or generate a random one. The passphrase (seed) is derived from the mnemonic and is one-way only.
Note: The BIP39 passphrase (seed) is derived from the mnemonic. The process is one-way and cannot be reversed. Never share your mnemonic or seed with anyone.
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]
Where:
Entropy = Random data converted to words
Checksum = First N bits of SHA256(entropy)
| 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