While some may argue about the importance of locking your iPhone or other iOS device with a passcode, in this day of identity thieves and other ne’er-do-wells, it’s generally something we here at iLounge strongly recommend users do. In fact, if you’ve got a device with Touch ID, there’s really little good reason to not have a passcode, which was Apple’s primary motivation for introducing the feature.

While you probably already know how to set a standard four-digit passcode, you may not realize that it’s possible to use more complex alphanumeric passwords as well — a good security feature considering the number of brute-force attacks that can defeat relatively simple four-digit PINs.
While having to enter a complex password each time you unlock your device would have been more cumbersome in the days before Touch ID, it’s much more practical now, as this is a password that you’ll need to enter far less often — usually only when you restart your device.
To enable a complex passcode, simply go into your iOS Settings app, choose Touch ID & Passcode, enter your existing passcode (if you’ve set one), and then scroll down and toggle OFF “Simple Passcode.” You’ll be prompted to change your old passcode as soon as you toggle this option off so that you can pick a more secure alphanumeric password.
Once you’ve done this, you’ll see that the iPhone unlock screen now presents a standard keyboard when you swipe to unlock your device.
However, using a complex password doesn’t change the way Touch ID works — you can still unlock simply by holding your finger on your home button, so you’ll rarely even see the full-keyboard unlock screen. A more secure password, however, will make your iPhone harder to get into for anybody who doesn’t have their fingerprint registered on your device.
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