As the local police department might want to decrypt a phone of a criminal suspect, so would the Chinese or the Russian or the Iranian intelligence agencies like to be able to do exactly the same thing.

If we try to prohibit encryption or discourage it or make it more difficult to use, we're going to suffer the consequences that will be far reaching and very difficult to reverse, and we seem to have realized that in the wake of the September 11th attacks. To the extent there is any reason to be hopeful, perhaps that's where we'll end up here.

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.

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.

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.

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.

If it were possible to hold onto this sort of database and really be assured that only good guys get access to it, we might have a different discussion. Unfortunately, we don't know how to build systems that work that way. We don't know how to do this without creating a big target and a big vulnerability.