Rare yes, impossible no... The main point of freenet is that nobody can prove beyond a reasonable doubt ... anything ... about anyone ... using freenet.
--b On Wed, 10/15/03 at 18:34:34 -0700, Martin Stone Davis wrote: > Pcaching only kicks in when the DS is 90% full, I thought. So it > wouldn't apply to a node which kept a huge DS. > > Also, isn't it the case that when inserting a large splitfile, the > various parts go through many different nodes? ...and so it would be > rare for you to have every part if you hadn't requested it. > > -Martin > > Brandon Low wrote: > > >I believe that pcaching applies to local requests too... so why not just > >let freenet take care of itself and stick to plausible deniability? You > >could just have been the first person in line for the insertion of said > >key or whatever... > > > >--B > > > >On Wed, 10/15/03 at 18:14:21 -0700, Martin Stone Davis wrote: > > > >>AFAIK, it is possible right now to discover whether a node has requested > >>a particular large splitfile by measuring how much time it takes the > >>node to search for each part of the splitfile. > >> > >>To prevent such "timing attacks on the datastore", I thought at first > >>that a solution would be > >> > >>SOLUTION #1: that the the node itself would flag any keys that the > >>operator has requested as "requested only by me". Then, if the node was > >>asked later for a key that held such a flag, it would pretend that it > >>didn't have it, search for the key on other nodes, and then reset the > >>key's flag if it found it on another node. > >> > >>However, Iakin (I believe) pointed out that this is a bad idea because > >>we don't want freenet itself to break it's own anonymity: we don't want > >>someone to be able to inspect the operator's hard drive and say "ah ha! > >>you requested this key!". > >> > >>He suggested instead (if I understood correctly) > >> > >>SOLUTION #2: that keys that we request would somehow be moved into a > >>separate, encrypted store, and never placed in the main datastore. > >> > >>However, isn't there a problem with that as well? > >> > >>Say that over a long period of time, node A requests keys K1-K1000 from > >>node B. K1-K100 were requested by the operator of node A, while > >>K101-K1000 were requested by nodes connected to node A. Also, K1-K100 > >>are all related to documents describing plans to overthrow the evil > >>government of AAIR (it's a tropical country which depends mostly on > >>tourism). Node B is run by (you guessed it) the AAIR. At the same > >>time, the AAIR is running another node C, which mounts a timing attack > >>on node A to see whether it has keys K1-K1000. Under either solution #1 > >>or #2, node C would see that node A takes longer to find keys K101-1000 > >>than it does to find keys K1-K100. But since the AAIR know that node A > >>requested all of the keys, it also knows that the operator of node A > >>requested keys K1-K100 and is trying to hide that fact. > >> > >>Note that in the above scenario, K1-K100 don't have to be part of the > >>same splitfile. They just have to be of similar-enough subject matter > >>that the operator of node A would appear to have requested it IF someone > >>were to inspect his datastore. > >> > >> > >>I'm having a lot of trouble coming up with a good solution. Thoughts? > >> > >>-Martin > >> > >> > >>_______________________________________________ > >>Devl mailing list > >>[EMAIL PROTECTED] > >>http://dodo.freenetproject.org/cgi-bin/mailman/listinfo/devl > > > _______________________________________________ > Devl mailing list > [EMAIL PROTECTED] > http://dodo.freenetproject.org/cgi-bin/mailman/listinfo/devl _______________________________________________ Devl mailing list [EMAIL PROTECTED] http://dodo.freenetproject.org/cgi-bin/mailman/listinfo/devl
