From: "Wei Dai" <weidai@eskimo.com>
Date: Thu, 26 Jan 95 15:48:07 PST
To: Andrew Lowenstern <andrew_loewenstern@il.us.swissbank.com>
Subject: Re: Reordering, not Latency (Was: Re: Remailer)
Message-ID: <199501262347.AA24792@mail.eskimo.com>
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Andrew Lowenstern asks:

> Is this even technically possible?  That is, wholesale monitoring of  
> disparate portions of the net from a single access point.  Given the  
> distributed and dynamic properties of the Net this would seem impossible.  To  
> monitor the entire remailer network an attacker would have to setup packet  
> sniffers upstream from each and every portion of the Net that contained a  
> remailer, wouldn't they?

Given the current state of computer security, this should 
not be too difficult for an organization such as NSA.  For 
each remailer, just hack into a computer on its local 
ethernet and put it into promiscious mode.  Each time an 
e-mail passes by, have it send the header to some monitoring 
center using an UDP packet.

> I suppose an extremely resourceful attacker could monitor traffic at crucial  
> points (i.e. transcontinental feeds, points on the NFSnet, CIX, etc...), but  
> there are so many private connections linking networks that it would be very  
> difficult indeed to sniff out every bit of remailer traffic.  Is having every  
> bit of remailer traffic necessary for traffic analysis?  Or would having a  
> good percentage of it be sufficient?

Complete monitoring should not be neccessary, having a 
larger percentage of the traffic just makes the job easier.

Wei Dai


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E-mail: Wei Dai <weidai@eskimo.com>   URL: "http://www.eskimo.com/~weidai"
=================== Exponential Increase of Complexity ===================
--> Big Bang --> atoms --> complex macromolecules --> biological evolution
--> central nervous systems --> social learning --> symbolic communication
--> computers --> internetworking --> close-coupled automation
--> high-bandwidth brain-to-net connections --> artificial intelligence
--> distributed consciousness --> group minds --> ? ? ?