Friday, August 18, 2006

Finding jammers in a DC network

David Chaum's dining cryptgraphers network is a nifty alternative to his digital mix to untraceably share encrypted information. But it suffers from the problem that since the participants are untraceable, one or more of them can jam the channel, preventing other participants from having their messages received. Bryan Turner has figured out a way to find the jammers if they are less than one-third of the total participants. Presumably this is accomplished without being able to find out much of anything else interesting about a participant. I suggest that a similar technique may also work for a jamming attack in a secure multiparty computation.