Digital home 101: Smart locks to defend your house

When Jason Johnson comes home each night, his front door unlocks before his hand even reaches the knob. The deadbolt knows he's approaching, recognizes him as Jason Johnson, and automatically opens the door.

This touch of science-fiction wizardry comes courtesy of an August Smart Lock. The door attachment works with old-fashioned keys, but also accepts wireless, digital "keys" emitted by smart phones.

"For several hundred years, we've used jagged metal objects to access our homes, but if you look at our cars and many of our offices, we've gotten rid of those keys," says Mr. Johnson, cofounder and chief executive of August. "Really, the last place to get electronic access is the home."

By this spring, at least six companies will sell keyless locks made specifically for homes. Traditional lockmakers such as Yale and start-ups such as August and Goji want to open up front-door technology and usher in an age of electronic "smart" locks.

Each of these new entry systems takes a slightly different approach. Yale designed its Real Living locks ($160 to $275 each) around a simple keypad. Cover the touch screen with your hand to lock the door; tap in your personalized code to open it. Yale designed Real Living to play well with home security systems, such as those from ADT, Time Warner, or AT&T. These extra systems allow for a lot of customization beyond the locks' basic features.

The Goji Smart Lock ($278 for pre-orders, $299 when it goes on sale in March) eschews a keypad. It uses Bluetooth wireless signals, either from a smart phone or a Goji keychain fob ($45). Each device emits a different code, so the lock knows not only that you're on the list, but also whether you're the owner of the house, the baby sitter, or the plumber.

The Goji lock comes with a motion sensor and camera, "so if anyone knocks, we send you an alert with a picture of who's at the door," says Gabriel Bestard-Ribas, founder and chief executive of Goji.

The August Smart Lock ($199 upon release this spring) allows an owner to send out temporary digital keys to anyone's iPhone or Android device. For example, you may invite the cleaners to let themselves in during a scheduled appointment. Once time is up, August automatically revokes their access.

All three of these lock systems are battery operated, so doors will open even during a power outage. Mr. Bestard-Ribas estimates that an average family of four will need to replace the batteries once a year. The lock systems also accept physical keys as backup. While each of the three locks looks rather elegant from the outside, each comes with bulky enclosures on the inside of the door that house the electronics and power pack.

Of course, with digital locks come new concerns over hacked front doors. As its final step before full production, August sent its smart locks to a cybersecurity firm. "We said basically, 'Hack it. Try to break into the system,' " says Johnson. "If all goes well, they won't be able to, and we'll get their stamp of safety certification."

With multiple layers of digital security built in to most smart locks, a determined burglar would be better served by simply going through a window. That's why smart locks often come as part of a more comprehensive home security system, one that can protect against many forms of home invasion.

Still, this trend toward phones becoming a universal remote control for the home worries Domingo Guerra, president of the security group Appthority.

"Almost 80 percent of people don't use any sort of lock screen on their phone," he says. "So even if it's not stolen – even if you just leave your phone somewhere for an hour or two – people could get into your phone and gain control of a lot more."

In other words: Don't spend hundreds or thousands of dollars defending your home, and then forget to adequately protect your phone.

For more on how technology intersects daily life, follow Chris on Twitter @venturenaut.

This article ran in the February 3 issue of the Christian Science Monitor magazine.