What encryption lets us do is say, "Yes, the Internet is insecure." Bad guys are able to compromise computers everywhere, but we're able to tolerate that because if they do intercept our messages, they can't do any harm with it.

There's been a certain amount of opportunism in the wake of the Paris attacks in 2015, when there was almost a reflexive assumption that, "Oh, if only we didn't have strong encryption out there, these attacks could have been prevented." But, as more evidence has come out - and we don't know all the facts yet - we're seeing very little to support the idea that the Paris attackers were making any kind of use of encryption.

It may be true that encryption makes certain investigations of crime more difficult. It can close down certain investigative techniques or make it harder to get access to certain kinds of electronic evidence. But it also prevents crime by making our computers, our infrastructure, our medical records, our financial records, more robust against criminals. It prevents crime.

The perspective that law enforcement is presenting seems to be a very narrow one that's focused very, very heavily on investigations of past crimes rather than on preventing future crimes. It's very important for policymakers to take that broader view because they're the ones who are trusted to look at the big picture.

Clipper took a relatively simple problem, encryption between two phones, and turned it into a much more complex problem, encryption between two phones but that can be decrypted by the government under certain conditions and, by making the problem that complicated, that made it very easy for subtle flaws to slip by unnoticed. I think it demonstrated that this problem is not just a tough public policy problem, but it's also a tough technical problem.

Computer science doesn't know how to build complex systems that work reliably. This has been a well-understood problem since the very beginning of programmable computers.

When the September 11th attacks happened, only about a year later, the crypto community was holding its breath because here was a time when we just had an absolutely horrific terrorist attack on U.S. soil, and if the NSA and the FBI were unhappy with anything, Congress was ready to pass any law they wanted. The PATRIOT Act got pushed through very, very quickly with bipartisan support and very, very little debate, yet it didn't include anything about encryption.