If you live in a state bordering Canada or Mexico, you may soon be given an opportunity to carry a very high tech item: a remotely readable driver’s license. Designed to identify U.S. citizens as they approach the nation’s borders, the cards are being promoted by the Department of Homeland Security as a way to save time and simplify border crossings. But if you care about your safety and privacy as much as convenience, you might want to think twice before signing up.