Rep. Craig Hall, a West Valley City Republican, has revealed that he is working on legislation that would allow the state to issue phone-based licenses.Hall made the proposal to the to the legislature's Transportation Interim Committee this week, saying that the mobile ID could be totally voluntary.Several states including Iowa, Arizona, Delaware and others are discussing or developing pilot programs to accomplish the same thing, reported The Salt Lake City Tribune.Hall cited a host of potential benefits, such as the driver license would always be with the person carrying the phone, it could be instantly updated via an app for such things as new addresses, and it may be more secure than plastic cards by requiring a PIN or biometrics (such as facial recognition) for use.He also noted potential challenges.One is counterfeiting. "It seems like it would be pretty easy to Photoshop" or duplicate with computers, said Rep. Stewart Barlow, R-Fruit Heights."Does everyone feel comfortable giving their phone to a police officer to take back to their police car? Could an officer snoop around in other parts of your phone? This is a legitimate concern. But there are solutions," said Hall.