Secure your phone (and everything on it)

Your new smart phone begins collecting personal information about you the moment you turn it on. Before long, it becomes a treasure trove of data about your location, friends and family, e-mail, browsing habits, even bank accounts. That's why we advise you to secure your device as soon as you start it up. Here are three steps we recommend:

Use a lock code

Your phone's display is the first line of defense against prying eyes. Lock it with a strong pass code (PIN or password). The longer the code, the harder it is to crack—six characters is a good minimum. Using a mix of letters, numbers, and symbols also enhances security. Fight the temptation to base your pass code on a year, name, or phrase, particularly one that's obviously associated with you.

Other effective options: the Touch ID fingerprint reader found on the Apple iPhone 5s or, on Android phones, the ability to unlock the phone's screen by tracing a pattern on it with your finger (shield the phone so that bystanders can't see what you're doing). Face scanning is another Android option, though it's not very reliable.

Encrypt your phone

This file-scrambling technique is one of the best ways to protect your phone's contents from unauthorized eyes. The phone's operating system unscrambles the encryption when you turn the phone on and enter the passkey. Encryption is built into the hardware of the iPhone 3GS and later models, and it's automatic if you have a pass code (screen lock) enabled. To set it up, tap Settings, then General, then Passcode.

On phones running Android version 4.0 or later, the encryption option is a feature of the operating system. To enable it, go to Settings, select Security and then Encrypt phone, where you'll be prompted to enter a PIN or password. Setting up encryption on an Android phone can take about an hour, so make sure it has enough battery life or is plugged in to a power source.

One thing you'll notice about your encryption-enabled Android phone is that turning it on or restarting it will take noticeably longer than without encryption. And the only way to turn off the encryption feature is by performing a factory reset on the phone, which erases your files and settings. If you go that route, make sure you have backed up your device first.

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Set up a phone-finding app

The same GPS and network connections that help you find nearby restaurants and the fastest way home can help you find a misplaced phone and remotely delete your personal information.

With a phone-finder app or service such as Apple's free Find My iPhone or Google's Android Device Manager, you can locate your phone on a map when you log in to the service from another phone or computer. Once your phone is located, you can have it make a loud noise. That can either direct you to its hiding spot under the couch or expose a thief.

In case you still can't locate your phone, those services can send a signal to erase the data stored in it. Find My iPhone is pre-installed on all iPhones, and Android Device Manager is pre-installed on some Android phones. It's also accessible at google.com/android/devicemanager, where it links to your Google account.

Third-party apps include Lookout Premium for Android, which charges $30 per year for remote lock and wipe, and also backs up photos, contacts, and call history, which can be transferred to a new device.