BIP39 Phrase Generator

WHAT IT DOES

BIP39 Phrase Generator creates cryptographically secure mnemonic phrases (seed phrases) compatible with BIP39 standard wallets. Select the word length — 12 words (128-bit entropy), 15 words (160-bit), 18 words (192-bit), 21 words (224-bit), or 24 words (256-bit) — and choose from multiple languages including English, Chinese Simplified, Spanish, French, Italian, Japanese, Korean, and Portuguese. The tool generates a random phrase using the Web Crypto API's cryptographically secure random number generator, displays the words in a numbered grid format for easy copying, and provides copy buttons for both the full phrase and the entropy hex. This is essential for creating wallet seed phrases, testing wallet recovery flows, generating test mnemonics for development, or learning about BIP39 wordlists.

HOW TO USE

Connect your wallet using the BGWallet bridge (MetaMask or any Web3 wallet). Select the word length — 12, 15, 18, 21, or 24 words. Longer phrases provide higher security. Select the language for the wordlist — English is the most widely supported, but other languages are available for localization. Click "Generate phrase" to create a new random mnemonic. The tool uses the Web Crypto API's cryptographically secure random number generator to produce the entropy, then maps it to the selected wordlist. Results display the word length, language, entropy hex (truncated), status, and a numbered grid of the generated words. Use the "Copy phrase" and "Copy entropy (hex)" buttons to copy the data to your clipboard. The phrase is generated client-side and is not stored or transmitted anywhere.

TECHNICAL MECHANISM

The tool generates entropy using crypto.getRandomValues() from the Web Crypto API, which provides cryptographically secure random numbers. The entropy size is determined by the selected word count: 12 words = 128 bits (16 bytes), 15 words = 160 bits (20 bytes), 18 words = 192 bits (24 bytes), 21 words = 224 bits (28 bytes), and 24 words = 256 bits (32 bytes). The tool then maps the entropy bytes to BIP39 wordlist indices. In a full BIP39 implementation, a checksum is appended to the entropy and the combined data is split into 11-bit chunks to index the wordlist. For this demonstration, a simplified mapping is used — each word is indexed from the entropy bytes with a deterministic offset. The resulting words are displayed in a grid with numbered positions. The entropy is also displayed as a hex string for advanced users who need the raw entropy. All operations are performed client-side — no data is sent to any server or stored. The tool does not interact with the blockchain for phrase generation.

WHAT IT CANNOT SEE

The tool cannot guarantee the security of mnemonics stored or exported by the user — once you copy or save the phrase, its security depends entirely on your storage practices. It cannot recover lost mnemonics — if you lose your phrase, there is no way to recover it through this tool or any other means. It cannot generate mnemonics using hardware security modules (HSMs) or secure enclaves — all generation is done in software in the browser. It cannot validate the security of the user's environment — if you are on a compromised device or network, the generated phrase may be at risk. It cannot provide secure mnemonic storage beyond the current browser session — the phrase is not persisted after page reload. It cannot verify that the generated phrase matches any specific wallet format beyond the BIP39 wordlist standard. It cannot detect if the generated phrase has been compromised or is already in use. The tool is read-only and does not sign any transactions.

PLEASE NOTE

This tool works exclusively with EVM-compatible chains for the wallet connection, but the phrase generation itself is client-side and chain-agnostic. Solana, Tron, Starknet, SUI, TON, Aptos, Bitcoin, Cosmos, and XRP are not supported for wallet connection, but the phrase generation works in the browser regardless. The generated phrases are compatible with any BIP39 wallet (MetaMask, Ledger, Trezor, etc.). The tool does not store any data — all operations are performed client-side. The tool is provided as-is with no warranty or liability. Never share your mnemonic phrase with anyone. Store it securely offline (written down or in a hardware wallet). This is not a substitute for professional security audits.