How tech-savvy thieves can steal your house keys

You don't need to just worry about your online security anymore; now, cybercriminals can potentially invade your home in the real world, too -- all they need is your house keys.

Duplicating a key used to be a challenge, requiring a locksmith to use the original key to cut a copy. No more. In the last few years, a number of online locksmiths have cropped up. These sites and related smartphone apps all work more or less the same way: You photograph and upload images of the key, which are then used to create a physical copy of your key which is then mailed back to you.

Keys Duplicated is one such example. Alternately, some apps (like KeyMe) make a digital version of your key that you can take to a locksmith to make a duplicate without needing to have the original key in hand. The innovation: You no longer need to have custody of the key to go to a locksmith. Now, you only need access to the key long enough to take a picture of it.

That's convenient, but it also makes it much easier for criminals to get front-door access to your house. In theory, co-workers can photograph your keys when you leave them unattended on your desk at the office, or the valet service you use at a restaurant can photograph your keys at their leisure after you leave your car with them.

To see if a scheme like this would work, a television news team from Kansas City, Missouri, photographed a house key, uploaded it to an online key duplication service and used the key to successfully gain access to the house in July.

That's not the end of the story. With the rise of affordable 3D printing, it will likely soon be possible for anyone to print duplicate keys locally without having to bother sending them to an online key duplication service or visiting a local locksmith. Homeowners can probably sleep secure for the time being, though, as plastic keys generated by today's generations of 3D printers lack the resolution and strength to actually unlock real doors. In a few years, though? This could be a concern.

The lesson? Like online security, a little common sense goes a long way. Never leave keys unattended, and certainly don't hand them off to strangers -- keep them separate from car keys for times when you need to leave them with a valet or auto mechanic.

You can bolster the security of your front door, as well. Smart locks like KEVO and Yale Z-Wave let you get into your house via your smartphone or entry codes, so you can leave the key at home where it can't be surreptitiously copied.