Information theoretically secure communication networks

[Tom Ritter]

On 12 August 2013 10:21, John Preston <gizmoguy1 at gmail.com> wrote:
> Consider a broadcast network: an eavesdropper cannot tell who a message
> is intended for from just the transmission itself. By using asymmetric
> encryption, the contents of the message can also be made unreadable to
> the eavesdropper and all unintended recipients, still preserving perfect
> single fact anonymity.
>
> Over time, an attacker could determine the intended recipient by looking
> at who sent messages within a certain time frame from receiving a
> message: the information gain from this is increased substantially if
> certain information about the protocol of the messages is known (e.g. if
> we're anonymising a real-time protocol, timed traffic analysis can
> reveal an intended recipient with a high degree of certainty). This can
> be defeated by including noise in the network: peers constantly produce
> garbage packets.
>
> I believe that this would yield information theoretically secure
> anonymity, as an attacker is looking for hay in a haystack, so to speak.
> Obviously, the problem with this protocol is that it is horrendously
> inefficient.

As Lance said, this is pretty close to what alt.anonymous.messages
evolved into in the 90s and early 00's.

I gave a talk two weeks ago looking at 10 years of messages there and
finding user errors, weak passwords, user-segmenting settings, and
traffic patterns.  Details are over here:
http://ritter.vg/blog-deanonymizing_amm.html

-tom