A man poses holding his cell phone Monday, Jan. 13, 2014, in Minneapolis. Lawmakers in the Minnesota House face a pre-filing deadline for bills ahead of the 2014 legislative session. A lawmaker is seeking a bill to require that providers include a "kill switch" to remotely disable lost or stolen phones. (AP Photo/Jim Mone) ORG XMIT: MIN2014021317040748 (The Minnesota Star Tribune)

On Thursday, U.S. Sen. Amy Klobuchar introduced a bill that would mandate the creation of "kill switch" technology in new cellphones. While the intent of this bill is to deter theft, its effect would be to create a powerful new tool that would erode civil liberties and make cellphones a more appealing target for hackers.

The proposal is intended to eliminate the market for stolen cellphones. As the thinking goes, since thieves could not sell a disabled phone, the incentive to steal them would be removed and thefts would decline. But mandating the creation of new technology often has unintended consequences. Cellphones have evolved to become essential for communication. This bill would take the freedom to communicate away from the consumer and place it in the hands of a telecommunications carrier.

It's not just carriers who could utilize this technology. If cellphones were required to be equipped with a kill switch, the power to disable a phone would become a tool that anyone with readily attainable skills could wield, including hackers and law enforcement personnel.

In fact, technology that could be used to activate kill switches is already in the hands of Minnesota law enforcement agencies. Both the Hennepin County Sheriff's Office and the state Bureau of Criminal Apprehension can impersonate cellphone towers using so-called Kingfish devices.

The temptation to abuse this "tower-spoofing" technology would only rise if kill switches become mandatory, creating a chilling effect on speech. Would citizens, for example, feel free to film the police knowing that law enforcement agencies could disable their cellphones?

Of course, the ability to spoof a cellphone tower is not the exclusive domain of law enforcement authorities. Hobbyists and hackers already are capable of "building" cellphone towers, and if hardware kill switches were required, these towers would have the newfound ability to disable any phone that would connect to them.

While that may not seem like an immediate threat, it is one example of what could happen when certain types of technology are legislated into existence. Technologies intended to disable the functionality of communications equipment should be regarded with apprehension and with the understanding that those who control this technology may not always be accountable to the public.

There is also a possibility of an adverse impact on the public. Could a consumer purchase a used cellphone with confidence knowing that the owner might later declare it stolen? To prevent this, perhaps anyone who sells a phone on eBay would be required to report the deal to a phone carrier, further complicating what was once a simple transaction.

There are other ways to deter the sale of stolen phones. In 2012, the Federal Communications Commission mandated that carriers work together to create a stolen cellphone database, which was completed in November. While it's too soon to know whether this will deter theft, a similar database created several years ago in Europe has met with moderate success.

The best way to prevent smartphone theft is personal responsibility. Many of us carry valuables in our wallets and purses, yet those items cannot have kill switches installed. I rarely see anyone absorbed in a game of Angry Birds on their wallet. Thieves target those who are unaware of their surroundings, so paying more attention is one step you can take to prevent theft today.

While the advocates of this legislation are well-intentioned, they are not technology experts. A mandatory cellphone kill switch would create more problems than it solves.

Anton Schieffer is a security researcher at LuciData in Minneapolis.