A BIP39 passphrase is an optional secret that is combined with your recovery words to derive a wallet. It is not a password that merely unlocks an existing wallet: the same recovery words with a different passphrase create a different, separate wallet.

A passphrase can add protection in some threat models, but it also adds a serious recovery risk. To restore a passphrase-protected wallet, you need both the exact recovery words and the exact passphrase.

What a BIP39 passphrase is

BIP39 is a widely used standard for recovery words. It allows a wallet to use an optional passphrase when converting recovery words into the wallet seed. That seed is then used to derive accounts, private keys, and receiving addresses.

The passphrase is separate from the recovery words. It is not included in the recovery-word backup, and it is not an additional recovery word. Terms such as “13th word” or “25th word” are common, but misleading.

The BIP39 specification uses an empty passphrase when no passphrase is entered. This opens the standard wallet derived from the recovery words alone. Entering a specific passphrase derives a separate wallet instead.

How a passphrase creates separate wallets

Each distinct passphrase produces a different wallet from the same recovery words. The process is deterministic: entering the same recovery words and the exact same passphrase again recreates the same wallet.

• No passphrase: opens the standard wallet derived from the recovery words alone.
• One specific passphrase: opens one separate wallet.
• A different passphrase: opens another separate wallet.

Every passphrase is valid from the wallet’s perspective. If you enter one character incorrectly, the wallet usually opens a different, empty wallet rather than reporting that the passphrase is wrong. Your funds remain in the wallet created with the original passphrase, but you must enter that exact passphrase to access them.

For the technical definition, see BIP39: mnemonic code for generating deterministic keys. The specification describes how recovery words and an optional passphrase are used to derive the wallet seed.

What a passphrase does and does not protect

A passphrase can keep a wallet inaccessible to someone who obtains only your recovery words. This can support a backup design in which the recovery words and passphrase are protected as separate secrets.

It does not make weak storage practices safe. If someone obtains both secrets, they can restore the wallet. A passphrase also cannot protect a wallet after you reveal the passphrase itself, approve a malicious transaction, or lose control of a device that already has access to the wallet.

For most people, securely storing recovery words offline is more important than adding a passphrase. A passphrase is an advanced choice, not a requirement for using a hardware wallet safely.

Decide whether a passphrase is right for you

Consider a passphrase only if you understand why it addresses a risk you actually face and can manage the added recovery complexity for the long term. Do not use one simply because it appears to add another layer of security.

A passphrase may be appropriate when you have a well-defined threat model and a robust plan to protect two separate secrets. It may be a poor choice if you rely on memory alone, share access with people who may need to recover the wallet, or are uncertain how you would restore the wallet years from now.

Create a safe passphrase recovery plan

Your recovery plan must account for both secrets. Record the passphrase accurately, including capitalization, spaces, punctuation, and any other characters. Keep it offline, and do not store it together with the recovery words if the purpose is to reduce the impact of one copy being stolen.

Do not rely only on memorization. Memory changes, and a person who inherits or needs to restore the wallet may not know the passphrase. At the same time, creating multiple copies or splitting information across locations creates its own loss and coordination risks. Choose a plan you can maintain and explain to any trusted recovery person, if applicable.

Before transferring meaningful funds, test that you can access the intended passphrase wallet consistently. A small test transaction can help confirm that you recorded the passphrase correctly and understand which wallet you opened. Never enter recovery words into a computer, smartphone, website, browser extension, password manager, cloud service, or AI chatbot.

For the underlying backup practices, learn how to securely store recovery words and how recovery words restore access to a wallet.

Use a passphrase with a BitBox02

The BitBox02 supports BIP39 passphrases as an optional advanced feature. The concept and recovery risk are not specific to BitBox: any compatible wallet used for recovery must use the same recovery words, the exact passphrase, and the relevant wallet settings to find the intended accounts.

After you understand the concept and have a recovery plan, follow the steps to set up an optional passphrase with a BitBox02. If you already use one, learn how to use and manage the BitBox02 optional passphrase.

A BitBox02 device password is different from a BIP39 passphrase. The device password unlocks a physical BitBox02; it is not part of the wallet backup. See the difference between a BitBox device password and an optional passphrase.

Frequently asked questions

Does a passphrase replace recovery words?

No. A passphrase is used together with recovery words. You need the exact recovery words and the exact passphrase to restore a passphrase-protected wallet.

What happens if I enter the wrong passphrase?

A different passphrase creates a different wallet, which will usually be empty. Your original wallet is still available, but only when you enter its exact passphrase. Do not send meaningful funds to a wallet until you have confirmed that you can reopen it reliably.

Can I change or reset a BIP39 passphrase?

No. Changing the passphrase creates a different wallet; it does not update the existing one. To use a new passphrase, first regain access to the existing wallet, then move the funds to a new wallet created with the new passphrase.

Can BitBox support recover my passphrase?

No. BitBox support cannot recover a passphrase and will never ask you to provide it. Anyone who obtains both your recovery words and your passphrase can control the funds in that wallet.

Should I use a BIP39 passphrase?

Usually, no—not unless you have a clear reason and a tested recovery plan. A securely stored offline recovery-word backup is the essential protection for every wallet. A passphrase is an advanced option that trades some protection against recovery-word exposure for a higher risk of human error and permanent loss.

For a longer discussion of the trade-offs, read the BitBox blog post Benefits and risks of using an optional passphrase.