Android lock-screen app turns camera into fingerprint scanner

ICE Unlock Fingerprint Secure promises an extra layer of security for your smartphone. But does it really work?

Rick Broida Senior Editor
Rick Broida is the author of numerous books and thousands of reviews, features and blog posts. He writes CNET's popular Cheapskate blog and co-hosts Protocol 1: A Travelers Podcast (about the TV show Travelers). He lives in Michigan, where he previously owned two escape rooms (chronicled in the ebook "I Was a Middle-Aged Zombie").
Rick Broida
2 min read
Diamond Fortress Technologies

Feeling a bit of iPhone 5S envy? After all, that built-in fingerprint sensor is pretty cool.

Small wonder, then, that rumors point to a similar sensor in the Samsung Galaxy S5. But you don't have to wait for that phone or abandon your current one just to reap the benefits of biometric security. Now, there's an app for that.

ICE Unlock Fingerprint Secure adds camera-powered fingerprint scanning to your smartphone's lock screen. That's not quite the same thing as the iPhone's scanner, and it's not nearly as efficient -- but it does work. Sort of.

After you install the app (which is free), it'll "enroll" your fingerprint by taking two photos of the finger of your choice. You need to place it "just so" within an onscreen oval, then tap the screen to capture a photo. If the two shots don't match, you'll have to repeat the process.

And it took me a few tries just to get enrollment right. (My tests were conducted on a Virgin Mobile ZTE Supreme. For whatever reason, the app isn't compatible with my Moto X.) After that, I was amused to discover that I couldn't unlock my phone, even though I'd finally "passed" enrollment. I couldn't seem to duplicate the proper positioning of my finger in that onscreen oval.

Fortunately, there's a PIN-based backup for just such emergencies. So I unlocked the phone that way, deleted my original enrollment, then tried the whole setup process again (following these tips). This time it went smoothly, and I had no trouble unlocking my phone with finger.

Until the lighting conditions changed. When I did the enrollment, it was indoors, and the LED had kicked in to better illuminate my fingerprint. But when I tried unlocking the phone outdoors, where there was tons more light, I couldn't get a match.

Needless to say, it can take some tweaking to get ICE working consistently. But I found it nearly impossible to unlock my phone with one hand, and there's no question that the fingerprint "scanning" adds a minimum of 5 seconds to the unlock process -- and that's assuming you hit a match the first time.

What's more, the presence of the PIN option raises the question of why you'd want to use this app at all. Answer: It's another layer of security, one that leaves no trace on your screen (unlike, say, a pattern-based password). That said, I think the hassle factor would quickly discourage most users.

On the plus side, ICE is free, so there's no harm in giving it a try. If nothing else, it's an interesting proof-of-concept for smartphone security.