There's nothing stopping you from upping the security ante with a longer PIN, or even a full-on password.
On an Android phone, you can create numeric PINs or alphanumeric passwords up to 16 characters in length, more than enough to stump casual crooks (assuming, of course, you don't pick a password like "password123456789").
Meanwhile, I tried creating a 50-character password on my iPhone, and iOS didn't stop me. Whether you really want a 50-character password is up to you, but the option is there for the taking.
Here's what you do...
For Android: Tap Settings > Security > Screen lock, tap either PIN or Password, then follow the steps.
For iOS: Tap Settings > Passcode, then disable the Simple Passcode option. Once that's done, you'll be prompted to create and verify a new passcode.
5. Encrypt your data [Android]
Good news for recent buyers of new Android phones or tablets with Lollipop (the latest version of Android) pre-installed: The data on your device is already encrypted, rendering it well-nigh indecipherable until it's unlocked with your passcode.
Older Android phones and tablets, however — including those that have been updated to Lollipop — don't have encryption turned on by default. Switching it on is a simple matter of a few taps, but it could take anywhere from half an hour (in my case) to several hours before all your data is fully encrypted, and you won't be able to use your phone or tablet during that time. You'll need to keep your phone plugged into its charger during the entire process.
Ready: Tap Settings > Security > Encrypt phone, then tap the final confirmation button.
Careful, though: Google warns that you could lose "some or all" of your data if you abort the encryption process midway through. And if you want to go back and turn off data encryption, you'll have to wipe your phone completely to do so.
6. Turn on Activation Lock [iOS]
Of course, plenty of phone thieves couldn't care less about your personal data. All they want to do is wipe and sell your precious handset.
A new iOS 8 feature called Activation Lock, however, will prevent anyone without the proper passcode from reactivating a lost iOS device, essentially turning it into an impeccably designed paperweight.
Pretty clever, but Activation Lock only works if you have "Find my iPhone" or "FInd my iPad" enabled on your device. To make sure, follow these (hopefully familiar) steps: Tap Settings > iCloud > Find my iPhone (or iPad), then make sure Find my iPhone/iPad is switched on.
7. Put your name and contact info on the lock screen [Android]
If your phone or tablet somehow manages to go missing, you can always use the handy Android Device Manager to lock your device and flash a "rescue" message on the lock screen. With any luck, a Good Samaritan will find your handset and get it back to you.
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