Two more things to keep in mind: First, some users report that encryption on Android caused a performance hit on their devices during everyday use. Second, encryption is irreversible—short of a factory reset.
All that said, if you want to encrypt an Android phone, here's how I did it on a device running the latest version of Android (4.3 Jelly Bean).
The screen at left shows paragraphs explaining exactly what Android app encryption involves. Once you're okay with that, tap Encrypt phone.
If you don't have a PIN or passcode set for your phone, you'll see a warning to set a passcode first. To set a passcode or PIN, go back to Settings > Security and tap Screen lock at the top of the page. From there, choose the option for either a PIN or a password. Android allows PINs to be greater than four digits.
After you've set up your PIN or password, go back to the encryption page and tap Encrypt phone again.
You'll be asked to enter your PIN, and then you'll be given one last chance to back out. If you're ready to commit, tap Encrypt phone one last time.
Now, all you can do is sit back and wait for your phone to encrypt itself. During the process, your phone could reboot several times. Don't touch it until you see the lock screen return.
Keep malware at bay
Android users are particularly vulnerable to malware. Google, unlike Apple, doesn't vet applications before they go live on Google Play. This has proven an easy way for malware creators to sneak malicious apps onto Google's app store. Malware-laden apps range from those offering free device wallpaper to games, and even to impostors that try to look like popular apps.
That's why security vendors such as Avast, Kaspersky, and Lookout offer antivirus and security apps for Android to help keep you secure online. But how good are these apps, really? Back in late 2011, results from independent security testing lab AV-Test found that the free solutions were nearly useless. The firm tested seven of the top free apps at the time and said that the best free solution detected only one-third of any malware present on a device. Even paid solutions weren't doing that great at the time of the 2011 tests, with the top paid apps detecting only around 50 percent of malicious code.
"When our report was published in 2011 the AV industry and the threat landscape was in a very early stage on Android," says Hendrik Pilz, director of AV-Test's technical lab. "Only a few malware existed but there were already several apps pretending to be an essential utility on each Android device." (Full disclosure: PCWorld regularly teams up with AV-Test to examine security software for PCs and mobile devices).
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