iPhone thieves may find that crime does not pay. A patent application published Thursday by the U.S. Patent & Trademark Office suggests that Apple has been developing security features for the iPod and the iPhone.

The patent application, Protecting electronic devices from extended unauthorized use, describes a way to prevent mobile devices from being charged following the failure of an authorization check.

"Unfortunately, theft of more popular electronic devices such as the Apple iPod music-player has become a serious problem," the patent application states. "In a few reported cases, owners of the Apple iPod themselves have been seriously injured or even murdered. Hence, techniques that can protect against unauthorized use and deter and reduce theft of such devices would be highly useful."

Apple's technique is to fight the power. The patent application envisions several possible tests that could be used to prevent a portable device from being recharged: "a timer expires, device is connected to a power-supply or another device, device is outside a determined geographical boundary."

When those conditions are met, Apple's software would ask the device user for an authorization code. Failure to enter the correct code would prevent the device from bring recharged. And as the patent application rather dryly puts it, "normal use and enjoyment of the device can be significantly reduced by disabling the recharger."

This approach may not protect confidential data, but it could reduce the incentive to mug the slew of gleeful iPhone owners who are sure to appear in coming weeks.