Crime-prevention experts always warn against giving out spare keys or hiding copies outside your home. Some manufacturers use biometric technology to keep duplicate keys out circulation, including Kwikset, whose SmartScan dead-bolt door lock can recognize up to 50 different fingerprints.

The latest technology to enter the home-security market allows you to use your cellphone and computer to control and monitor access to your home.

The Schlage LiNK system is designed to let you log in and create temporary codes that a contractor or guest, for example, can enter into a keypad on the door lock. A module the size of a deck of cards connects to a broadband modem and uses encrypted radio-frequency signals to control the door lock. It will also send you a text message to alert you when your latchkey—or is that latchcode?—kid has arrived home.

The system retails for $300 and includes a standard lockset with a 10-number keypad and conventional key. Schlage charges a $13 monthly fee for the remote-access service, which you can also use to control devices that use the Z-Wave protocol, says the manufacturer. We have not tested this product.—Gian Trotta| e-mail | Twitter

Essential information: Read about some other ways to boost home security and avoid these burglar-alarm-company scams. And learn about the favorite tool of some crooks: bump keys.