Re: How do I know if its encrypted?

Of course, we're not just dealing with text. So the scheme has got to be changed a bit so as to be able to detect unencrypted GIFs, and mu-law files, and as yet to be determined unknown files. Each of these data formats has it's own regex recognizers available. Just apply them. The point, though, is to enforce the presumption that the remailer operator does not, in fact, look at the traffic in order to understand the content. You don't need a completely airtight algorithm in order to do this. Eric