On balance, the use of encryption, just like the use of good locks on doors, has the net effect of preventing a lot more crime than it might assist.

We basically have only two real tried and true techniques that can help counter this. One of them is to make systems as simple as we can, and there are limits to that because we can only simplify things so much. The other is the use of encryption.

So, in 1993, in what was probably the first salvo of the first Crypto War, there was concern coming from the National Security Agency and the FBI that encryption would soon be incorporated into lots of communications devices, and that that would cause wiretaps to go dark. There was not that much commercial use of encryption at that point. Encryption, particularly for communications traffic, was mostly something done by the government.

It's only after you get down into the technical weeds - and they are admittedly rather weedy - that it becomes clear that this is much harder than it seems and not something we're going to be able to solve.

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.

In order for any smartphone manufacturer to decrypt the data on your phone, it has to hold onto a secret that lets it get that access. And that secret or that database of secrets becomes an extremely valuable and useful target for intelligence agencies.

Telephone handsets are particularly in need of built-in security. We have almost every aspect of our personal and work lives reflected on them and we lose them all the time. We leave them in taxis. We leave them on airplanes. The consequences of one of these devices falling into the wrong hands are very, very serious.