Not a good idea. To me this comes under the heading of "If you outlaw it only outlaws will have it." If it's technically possible, the criminal crackers will be the first to do it; therefore we will have no secure communications. New York Times reports that:
Federal law enforcement and national security officials are preparing to ask Congress to require all services that enable communications — including encrypted message transmitters like BlackBerry, sites like Facebook and messaging software like Skype — to be technically capable of complying with a wiretap order.
The mandate would include being able to intercept and unscramble encrypted messages.