Passphrases

BIP-39 supports an optional passphrase, sometimes called the 25th word. It is mixed into the seed derivation, not stored, and not recoverable.

Two things the UI says plainly and this document repeats:

• A passphrase cannot be recovered. There is no reset. If you forget it, the funds are gone. It is not a password on an account, it is part of the key.
• A wrong passphrase does not produce an error. It produces a different, perfectly valid, empty wallet. This is the single most common way people lose funds with passphrase wallets.

Because of the second point, nullroute shows the wallet fingerprint at unlock and before any funds-related action. If you have used this passphrase before, the fingerprint will match what you recorded. If it does not match, you typed it wrong. Write the fingerprint down when you first create a passphrase wallet.

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