On Tue, Oct 28, 2003 at 11:22:02PM +0000, Toad wrote: > I have a better attack. You are targetting a particular area of the > keyspace. Request a long stream of random keys very close to the target > key. They will all DNF, and reduce the pDNF in that area of each node > the node routes the request to, until the estimator is so low that it > tries a different node. Keep on requesting and you can effectively > eliminate the node's ability to route requests in that region... I have > no idea how to fight this attack :(. Anyone have any reason why it > wouldn't work?
Here's a start: If pLegitDNF accurately reflects the attack, we have little to fear, because it will affect all nodes equally. Unfortunately getting an accurate pLegitDNF that varies per key is a bit of a bastard. Currently we use the lowest average pDNF (not per key) of those nodes in the RT which we alchemically choose to be mature enough to matter. This is not exactly satisfactory, of course, and to defeat this attack we need an accurate pLegitDNF which takes the key as a parameter. We used to use the same alchemical choice on the estimators for the key we were routing, which would seem to solve the problem - but it turns out that the estimators may well not have learned much in the area of the key we are searching for, and result in an absurd estimated pDNF. We have maturity data (total amount of influence on a given point) provided by the NGRouting aging algorithm, but we would have to set an arbitrary cutoff point, which we must presumably determine empirically... -- Matthew J Toseland - [EMAIL PROTECTED] Freenet Project Official Codemonkey - http://freenetproject.org/ ICTHUS - Nothing is impossible. Our Boss says so.
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