"I oppose requiring companies to build back doors into their products," Sen. Ron Wyden (D-Ore.) tweeted during Comey's speech.
Earlier this year, Apple and Google both announced that the next versions of their mobile operating systems would be encrypted by default, which Comey says will make it far more difficult for law-enforcement officials to access user information.
And he says that he is sympathetic that the firms have come under fire from the perception that the government has ready access to their data, though he insists that default encryption is a dangerous overreaction that will impede law enforcement, suggesting that "the post- Snowden pendulum has swung too far."
"Both companies are run by good people who care deeply about public safety and national security. I know that," he says. "And they're responding to a market demand that they perceive, but the place that this is leading us is one that I suggest we should not go without careful thought and debate as a country."
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