Proposed bill would require kill switch in Calif. phones, tablets

California regulators are stepping up their efforts to deter smartphone theft.

State Sen. Mark Leno (D-San Francisco), San Francisco District Attorney George Gascon, and other regulators will introduce a bill on Friday that would require smartphones and tablets sold in the state to have software that would completely disable the device if stolen, a concept often referred to as a "kill switch." If passed, the bill would go into effect for any device sold after January 1, 2015.

The bill is the latest step taken by regulators to force more aggressive action to crack down on theft. The thinking is that if all mobile devices could be rendered obsolete if stolen, thieves wouldn't bother to steal them, a sort of LoJack for smartphones. Gascon had previously attempted to push the kill switch alongside New York Attorney General Eric Schneiderman, who together led the Secure Our Smartphone initiative.

By deterring smartphone theft, city officials are hoping to curb crime overall; half of all robberies in San Francisco and nearly three quarters of robberies in neighboring Oakland are related to smartphone theft.

In June, Gascon and Schneiderman said they were talking to some of the major players in wireless, including Apple, Google (via its Motorola Mobility unit), Microsoft, and Samsung Electronics. The regulators even applauded Apple for its decision to put an activation lock on a phone, which wouldn't let you wipe a phone and reactivate it without the username and password, but noted it wasn't a ubiquitous solution.

The regulators aren't necessarily looking for a kill switch that bricks a phone. But they are looking for a way to disable to core functions of a phone or tablet if it is stolen. Software options exist in the market but aren't widely used.

The industry, however, has proven resistant to the idea, noting potential security risks. The wireless carriers, in particular, rejected the idea, leading to some criticism from regulators. Schneiderman said he sent a letter to the heads of the five largest carriers in the US.

Instead, regulators are hoping to get around the resistance by passing a bill mandating the change. The bill has the support of officials from San Francisco, Los Angeles, and Oakland. But it's unclear how much political support it will receive.

While the bill only affects devices sold in California, regulators are hoping to inspire broader change, as it's unlikely the manufacturers would make a customized kill-switch-enabled smartphone or tablet just for one state.