On Jan 23 2008, Matthew Toseland wrote: > I am talking about a hypothetical, generalised scheme which doesn't have > the nearestLoc: weighted coin on the one extreme, and adaptations of the > current scheme without nearestLoc on the other.
OK, thanks. > So the probability that the requestor is the originator depends solely on > m: - The probability of the originator being the requestor given a > positive hop is 1/m. With a hop counter m is 1 + the number of resets, and with a weighted coin it's 1/pDrop, right? > - The probability of the originator being the > requestor given m positive hops (i.e. given n+m hops on average) is > 1-((1-(1/m))^m. Sorry, you've lost me again - we only see each request once, don't we? Here's how I see it: the path length is n+m. For a weighted coin, n=0. For a hop counter, n>0. The attacker gets a positive sample with a probability of m/(n+m), and for each positive sample there's a probability of 1/m that the previous hop is the originator. But the samples for a weighted coin are independent, whereas with a hop counter they're not, so given enough requests the attacker always learns more from a weighted coin. Cheers, Michael
