On Wednesday 23 January 2008 15:46, Michael Rogers wrote: > 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?
Yes, although n is debatable. > > > - 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? I mean given m requests which qualify as positive samples. > > 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. Why are samples for a hop counter dependant? > > Cheers, > Michael -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: not available URL: <https://emu.freenetproject.org/pipermail/devl/attachments/20080123/97a8b662/attachment.pgp>
