At 12:16 PM 6/6/96, Scott Brickner wrote: <SNIP>

The discussion was about multiple remailers from multiple accounts on the same machine. The very existence of the remailer, independent of issues like shuffling and chaining, is supposed to eliminate identifying the originator by the content of the message. Message shuffling, delays, and chaining are entirely for the purpose of reducing the information available to the traffic analyst. If several remailers are running on the same machine, they may be treated as if there were only one remailer, for the purpose of traffic analysis. Getting more traffic going through them just makes the analysts job easier, because his statistical conclusions are stronger. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

I don't think I am following you. My messages are a constant size signal (I send N messages through the remailer). More traffic increases the background signal and background noise. While the signal to noise of the background gets better, the actual amount of noise went up so the ratio of MY signal to the background noise went down. Perhaps I don't understand what you are saying. I think multiple remailers on a machine are less effective than a single remailer with the combined traffic of all the individual remailers, because the combined remailer does better reordering from a larger pool. If the remailer chain contains just two or more uncompromised hops (not necessarily consecutive) I suspect an attacker will be forced to treat the remailer bramble as a single object. This attack is based on time correlations of messages sent and received. In this case background traffic is good because of the large number of false correlations it generates. However, it is stunning how few messages it takes to make the correlation stand out. The defense against this attack is to ensure that you send and receive enough remailer mail to correlate with all other users for all messages. Producing cover traffic, some of which returns to you, and some of which is bit bucketed also ensures that it will not be known when you receive a real message (as opposed to one of your own). Obviously this is best done when you are a remailer operator yourself. -Lance (who will now dismount the soap box) ---------------------------------------------------------- Lance Cottrell loki@obscura.com PGP 2.6 key available by finger or server. Mixmaster, the next generation remailer, is now available! http://www.obscura.com/~loki/Welcome.html or FTP to obscura.com "Love is a snowmobile racing across the tundra. Suddenly it flips over, pinning you underneath. At night the ice weasels come." --Nietzsche ----------------------------------------------------------