But I have a (newbie?) question. Isn't it true that, at the network level, it is still possible to tell where a message came from and where it's going. That is, given the proper motivation, couldn't "and entity" sniff out all of this information and find out which machine a particular message came from. And from logs at that machine, which The Entity naturally has access to, It could find out who send the message. Just wondering.....

That is the point of encrypted, anonymous remailers. Since the message is encrypted, it looks like a random set of bits. If it gets re-encrypted at every stage, then the remailers can add random bits of data to change the size. They already change the headers. So, the only thing left to worry about is a FIFO problem. But that is easily solved. So, here is what happens: A message comes into a remailer (actually, a bunch of messages do, but that's not important). It comes in encrypted, so you can't read the message. The headers are stripped off in the remailer and the message is re-encrypted, so the data changes. If it gets stored an arbistrary length of time, and the outgoing order is different than the incoming order, than there is no way to figure out which message came from or went to where. There is a lot more to this, and a lot of other problems that need to be solved, but this is it in a nutshell. I hope it answers your question. I'm sure people will correct any mistakes I inadvertantly left in. -derek PGP 2 key available upon request, on the key-server: pgp-public-keys@toxicwaste.mit.edu -- Derek Atkins, MIT '93, Electrical Engineering and Computer Science Chairman, MIT Student Information Processing Board (SIPB) MIT Media Laboratory, Speech Research Group warlord@MIT.EDU PP-ASEL N1NWH