How California's kill-switch law could go awry

For some time now, the California legislature has debated, voted on and temporarily defeated measures to require a kill switch on mobile phones sold within the state. At long last, the debate is definitively over: Governor Jerry brown has signed Senate Bill 962, which mandates a kill switch on all smartphones sold in the state.

While the intentions behind the law seem sensible, opinions aren't exactly unanimous that it will work out the way its framers expect.

The law takes effect on July 1, 2015, and applies to smartphones but does not include feature phones or tablets and other mobile devices. It requires that smartphones come equipped with the hardware and/or software necessary to allow authorized users to remotely lock the handset and prevent it from being used in any way, including being resistant to having the operating system wiped, replaced or reset.

The Apple (AAPL) iPhone is already largely compliant with the new California law, except that the new law requires that the kill switch be enabled by default. The iPhone's activation lock feature doesn't yet function by default, though presumably that's a relatively simply update. Some Samsung Android phones are similarly equipped, though Google (GOOG) and Microsoft (MSFT) will need to implement this technology across its mobile OS by next summer.

The law is a response to concerns about incidents of smartphone theft. In cities such as Los Angeles, New York and Chicago, stealing iPhones from pedestrians has become so common it has its own name: Apple picking.

Some applaud the law as a measure that might reduce the incentive to steal smartphones. California Senator Mark Leno said, "Our efforts will effectively wipe out the incentive to steal smartphones and curb this crime of convenience, which is fueling street crime and violence within our communities."

But online forums are filled with criticism as well, pointing out that it will likely take years for the majority of phones on the street to be replaced with models that have kill switches.

And the phone's rightful owner isn't the only person who might be able to take advantage of the kill switch. The potential for widespread mischief is great when disgruntled spouses, ex's and other family members might maliciously activate the kill switch. The kill switch could also become a juicy target for hackers. And most chilling of all to some: The government would have access to the kill switch as well, and there's precedent for its use.

Back in 2011, San Francisco officials shut down cell phone access to commuters on the BART subways to thwart a planned protest. These days, a court order is theoretically required for most such actions by police, but that still worries many, including the Electronic Freedom Foundation, which opposed this law.

And because it makes no sense for manufacturers to make handsets just for California, the kill switch technology will invariably end up being embedded in phones sold worldwide. Governments with far fewer civil liberty protections for their citizens will get a new suite of tools for controlling speech and communication.

An unintended consequence of reducing crime on the streets of LA could dramatically curtail civil liberties around the globe.