FBI director James Comey on Wednesday called on tech companies providing smartphone encryption tools to voluntarily find ways to turn over to a judge those messages suspected of being terrorist-related.

"The government doesn't want a back door," Comey told the U.S. Senate Judiciary Committee. (See video, below.) "The government hopes to get to a place where if a judge issues an order, the company figures out how to supply that information to the judge and figures out on its own what would be the best way to do that. The government shouldn't be telling people how to operate their systems."

Comey said that some companies have designed their smartphones to provide terrorists' and crime-related communications to law enforcement, but others have not.

"It's actually not a technical issue; it's a business model question," Comey said. "A lot of people have designed systems so that judges' orders can't be complied with...The question we have to ask is: Should they change their business model?"