Wielding a smartphone makes you a walking target. That's especially true of iPhone owners, and unfortunately, smartphone mugging has become the new trend in criminal circles. In fact, it was previously reported
that half of all robberies in San Francisco so far in 2012 have been cell phone related, many of which took place in public places, like busy transit lines.
Smartphone security is something that needs to improve, and it's the driving force behind a new patent application Apple
filed with the United States Patent & Trademark Office (USPTO). The patent is for an acceleration-based theft detection system for portable electronic devices. In short, it relies on the accelerometer to determine if a theft has likely occurred. Here's how it's described.
"An acceleration sensor detects the acceleration of a portable electronic device, and a controller analyzes this acceleration to determine whether a theft condition is present," Apple explains in its patent application. "If so, an alarm can be initiated. The theft prevention system can include a filter for attenuating irrelevant acceleration frequencies and isolating those representative of theft, and comparison hardware/software for determining whether the detected acceleration matches a known acceleration profile characteristic of theft. Various parameters of the theft prevention system can also be set by a user through mechanisms such as a graphical user interface."
In order to prevent or reduce false alarms, the security mechanism would filter out acceleration signals corresponding to shock or impact, which would occur if you drop your device. There's a special signal filter and theft detection circuitry to address false alarms.
If a possible theft is detected, the user has a set amount of time to enter an alphanumeric passcode before the alarm sounds and/or the user is locked out of the device.