1 research outputs found
Filter Design for Delay-Based Anonymous Communications
In this work, we address the problem of designing delay-based anonymous
communication systems. We consider a timed mix where an eavesdropper wants to
learn the communication pattern of the users, and study how the mix must delay
the messages so as to increase the adversary's estimation error. We show the
connection between this problem and a MIMO system where we want to design the
coloring filter that worsens the adversary's estimation of the MIMO channel
matrix. We obtain theoretical solutions for the optimal filter against
short-term and long-term adversaries, evaluate them with experiments, and show
how some properties of filters can be used in the implementation of timed
mixes. This opens the door to the application of previously known filter design
techniques to anonymous communication systems.Comment: 201