Face ID, passcode or pattern: which lock is safest?

What each lock is

• A passcode or a password. Sealed’s default passcode is 6 digits, and you can choose 4 or 9 digits or a password instead.
• A pattern. A Sealed pattern is drawn on a grid of 3 by 3 up to 6 by 6 dots and has to connect at least 4 of them, and a drawing that is too short is told so and isn’t counted as a wrong try.
• Your face or fingerprint. Quick, and a face that doesn’t match counts as a wrong try.
• A lock screen style. A dial, a padlock, a word or a rhythm in place of the keypad. Every lock screen style is another way to enter your passcode, so it changes how you enter it and not how many combinations it has.
• Dual Lock and Maximum Security. Two options that change what a way in has to prove. They are below.

Three people, three different answers

No single lock wins every row. Pick the row that worries you, then read its section.

Against guessing: length

The wait is part of every vault: it doesn’t need Break-In Alerts or Sealed Pro. It turns every wrong try into minutes, then hours. With the limit left at three, trying every possible code takes this long:

A password, nine digits or a long pattern on a larger pad take longer still. A code with a shape, like a birth year, falls much sooner than any of these. The guide to guessing a passcode shows where the numbers come from and what shortens them.

Where face unlock is weaker

Face unlock is quick, and Apple’s own numbers are good. Apple says the chance that a random person could unlock your iPhone with Face ID is less than 1 in 1,000,000 with a single enrolled appearance, and higher for twins and siblings who look like you. Apple says Face ID allows only five unsuccessful match attempts before the iPhone asks for its passcode.

Apple says Face ID is attention-aware and recognizes if your eyes are open, which makes it more difficult for someone to unlock your device without your knowledge, such as when you are sleeping. That is about an unlock you don’t know about. A person who holds the phone up to you while you are awake is a different case, and Apple’s page makes no promise about it.

In Sealed there is one more gap to know about. With Face ID unlock on, and Dual Lock and Maximum Security off, Sealed asks iOS for owner authentication and not for a face match alone. In iOS, an app that asks for owner authentication gets Face ID or Touch ID first, and the device passcode when biometry isn’t available or the person taps the fallback button. With plain Face ID unlock on, someone who knows your iPhone passcode can open Sealed through the Face ID prompt.

If other people know your iPhone passcode, that matters. In Settings, under Passcode & Unlock, you can turn Face ID or Touch ID Unlock off, and set, change or remove a pattern.

What Dual Lock adds

Dual Lock guards the door: it asks for your passcode and then for your face. Dual Lock’s second step takes Face ID or Touch ID only: your iPhone passcode can’t stand in for it, so one watched passcode can’t do both halves. Dual Lock applies to a pattern as well as a passcode: after either, Sealed asks for your face.

It has a cost. If Dual Lock can’t ask for a face, because Face ID is off for Sealed or locked, the vault stays shut instead of opening on the passcode alone, and your recovery key can turn Dual Lock off. The Dual Lock page has the details.

What Maximum Security adds

Maximum Security guards the key, not the door. Without Maximum Security, the app can read your vault key whenever the phone is unlocked, because the key sits in the Keychain. With Maximum Security on, every unlock ends with a live Face ID or Touch ID match that releases your vault key. With Maximum Security on and Dual Lock off, a Face ID or Touch ID match alone opens the vault, with no passcode.

It has a cost too. Before you can turn on Maximum Security, Sealed asks you to save your recovery key, because it is the only way back in if your Face ID or Touch ID ever changes. The Maximum Security page explains when it is worth it.

A setup that fits most people

1. Use six digits or more. The table above shows why four digits is the length to move away from.
2. Keep face unlock on if you want speed, knowing what it accepts: your face, or your iPhone passcode.
3. If other people know your iPhone passcode, turn face unlock off in Sealed, or add Dual Lock.
4. If you want the key tied to your face, add Maximum Security, after you save your recovery key.
5. Save your recovery key and keep it private. Anyone who has your recovery key and your iPhone or your iCloud backup can open your vault. It is also the way past a wait: Forgot passcode? with your recovery key works during a wait, because a wait protects nothing against a 256-bit key.
6. Leave the auto-lock as it is. Sealed locks as soon as you leave it unless you choose a delay, and it covers its contents in the app switcher.

Where Sealed helps, and where it doesn’t

It helps by making guessing slow, by asking for two things when you turn Dual Lock on, and by tying the key to your face when you turn Maximum Security on. The wait is part of every vault: it doesn’t need Break-In Alerts or Sealed Pro.

It doesn’t do these things:

• Stop someone who watched you type, on its own. A passcode or a pattern that has been seen is known. Dual Lock’s second step takes Face ID or Touch ID only: your iPhone passcode can’t stand in for it, so one watched passcode can’t do both halves.
• Make your iPhone passcode irrelevant. Unless Dual Lock or Maximum Security is on: With plain Face ID unlock on, someone who knows your iPhone passcode can open Sealed through the Face ID prompt.
• Beat a person who can make your face match. With Maximum Security on and Dual Lock off, a Face ID or Touch ID match alone opens the vault, with no passcode. Dual Lock adds the passcode back.
• Get you in if you lose the passcode and the recovery key. Because your key never reaches us, we cannot recover your vault or reset your passcode for you.
• Fit every lock in the free plan. Dual Lock, Maximum Security and every style but the keypad are Pro. Every lock screen style except the Keypad is part of Sealed Pro.