BIP39 Passphrase

How the Passphrase Cryptography Works

Under the BIP39 standard, your 12 or 24 word seed phrase is transformed into a cryptographic master root key using a mathematical hashing function.

When you apply an optional passphrase: 1: The hardware device combines the 24 words with your custom passphrase string.

1. A completely new, independent set of private keys and public addresses is mathematically generated.
2. There is no such thing as an incorrect passphrase. Entering a different word simply generates a brand new empty wallet on the blockchain.

The Two Major Security Benefits

1. Protection Against Physical Coercion (Plausible Deniability):

You can maintain two separate wallets on one physical device:

• Standard 24 words: A decoy account with a small balance.
• 24 words plus Secret Passphrase: Your true vault containing the majority of your savings. If forced to unlock your device under physical threat, unlocking the standard wallet reveals only nominal funds while keeping your main balance completely invisible.

1. Protection Against Physical Seed Theft:

If someone physically steals or photographs your written 24 word paper sheet, they still cannot access your funds without knowing your custom passphrase stored securely in your memory.

Critical Rules for Using a Passphrase

1. No Recovery Mechanism: If you forget your custom passphrase, your funds are permanently lost. No wallet company or recovery tool can reset it.
2. Case Sensitive: Passphrases are strictly case sensitive. Capital letters, spaces, and punctuation alter the mathematical generation completely.

Learn how to safely set up and back up your hardware devices in our Complete Cold Storage Guide.