CDR: Re: Disposable remailers

[despot]

It is interesting to note the two sides of the same coin...mix protocols in theory vs the realities of implementation on these devices.

On Sat, 7 Oct 2000, Sean Roach wrote:
> If the net is sufficiently large, then the remailers can be 
considered to
> be registers, each holding one message for a random length of 
time, and
> allow reordering just by that alone.  Of course, for this to 
work, traffic
> analysis has to be defeated in another way.  Probably in ZKS's 
planned,
but
> last I checked, not implemented, constant activity among nodes.

This scheme is extremely open to attack, especially when you take 
into account that many of the nodes will be hostile. Even if the 
underlying mix protocol were robust enough to protect the sender 
over hostile nodes, traffic analysis, as you mentioned, is a major 
weakness (for example, messages could be traced throught the 
network).

The idea and papers brought forth in David's post might be of use 
here. Instead of passing one message at a time through nodes, a 
list of messages could filter through the nodes. But, those damned 
memory constraints...

> Of course, the more traffic, the easier it will be for the 
intranets where
> these things are set up to locate them, and take them down.

If the devices' communication piggy-backed on common protocols 
like http, it would be easier to mask, especially in high traffic 
areas. But, the communication would need to permuted in some way 
that a generic pattern match would not detect it. Otherwise, IDS 
vendors and the like will add rules to detect such traffic.

> The nodes ping each other on a regular basis, if a node fails to 
respond
to
> a ping, that node is written off.  Perhaps the next general 
cover traffic
> includes information that such-n-such node appears to be 
compromised.  If
a
> node receives NO pings, then it might also write itself off, and 
blank
memory.

Who do you trust becomes an issue if nodes pass information 
around.

> Or did you mean in addition to disposible remailers, instead of 
ways to
> hide, distribute them?

I meant in addition to, but that is an interesting distribution 
scheme.

As the world becomes more and more connected and devices get 
smaller and more powerful, the opportunity to plant and exploit 
rogue, networked modules becomes far greater. A person could have 
a great deal of fun with this stuff. The government already does.

-andrew