# PIN & Passphrase

A KeepKey has two separate, optional locks. They're easy to confuse, but they protect against completely different things. You can use one, both, or (not recommended) neither.

## PIN — guards the physical device

The **PIN** is a code you set during setup. It's required to unlock the device before it will do anything, so a thief who steals your KeepKey can't just plug it in and drain it.

Two details make it strong:

- **The number grid shuffles every time.** Your computer only ever sees *positions* on a scrambled keypad, not the digits — so screen-recording malware and over-the-shoulder watchers learn nothing reusable.
- **Wrong guesses get slower and slower.** After three wrong PINs the device makes you wait before the next try, and the wait doubles with every further failure (8 seconds, 16, 32, and so on). That makes brute-forcing impractical. If *you* forget it, wipe the device and restore from your [recovery phrase](/docs/learn/recovery-phrase) — a wipe is not a loss.

A PIN protects the **device**. It does *not* protect the recovery phrase — anyone who has your written-down words doesn't need your PIN at all.

## Passphrase — creates a hidden wallet

The **passphrase** (sometimes called a "25th word") is an optional secret you can add on top of your recovery phrase. Combined with your phrase, it derives an **entirely separate, hidden wallet**.

What makes it powerful:

- **It's never stored on the device.** It exists only in your head (and your secure backup). Even someone who physically extracts the device's stored seed gets nothing without the passphrase — which is why it's the strongest defense against a physical attacker. See the [Security](/docs/security) page.
- **Each passphrase = a different wallet.** Enter a different passphrase and you get a different set of accounts.

The trade-off: because it's never stored, **if you forget it, that hidden wallet is unrecoverable.** Write it down as carefully as your recovery phrase and test recovery before funding it.

## Which should I use?

- **PIN: yes, always.** It's basic device security with no downside.
- **Passphrase: for higher-value storage**, once you're comfortable with the backup discipline. It's optional and advanced.

## On your KeepKey

- Set up and learn the shuffled-grid PIN in [PIN](/docs/desktop/pin).
- Create and manage hidden wallets in [Passphrase (Hidden Wallets)](/docs/desktop/passphrase).
- See how both fit the overall threat model on the [Security](/docs/security) page.