On Fri, Nov 14, 2014 at 03:01:21PM -0800, travis+ml-lang...@subspacefield.org wrote: > On Fri, Nov 07, 2014 at 01:49:02PM -0800, David Fetter wrote: > > While there is such a thing as legal definitions of personally > > identifiable information, is the idea that this division exists, i.e. > > that information can be identified in a context-free way as implying > > other information, while other information cannot, even plausible? > > If I understand your question correctly, no. Case in point, using > Netflix ratings to identify political preferences: > > https://www.cs.utexas.edu/~shmat/shmat_oak08netflix.pdf
Yes, it's just this kind of thing that I had in mind. It seems to me that any information, however broad or trivial, could in some context be the "last straw" that sets the K in your K-anonymity to 1. > > My information theoretic background is pretty close to > > nonexistent, but my intuition says no. > > My ordinary rule is to be skeptical of any broad, or universal > claims - that such-and-such is always, or never, the case. Such > things are difficult to prove, though clearly falsifiable, something > which physical sciences should have taught me, but which for some > reason computer security still frequently surprises me with. I hope some day that computer science will be an actual science. At the moment, it appears to be a kind of abstruse branch of mathematics, which would be fine if it weren't *called* a science. Science has experiments that establish a model's connection to the universe in which we live, and falsifiability, and stuff like that. Mathematics has logical consistency, which is not even remotely the same thing, even though there's a school of flat-earth economics that says it is. > The difficulty of proving such is usually what is meant by "proving a > negative": negate(exist(A)) == universal(not(A)) > > As a matter of pedantry, "it is not the case that this room is > painted black everywhere" is proven by a spot of white: > negate(universal(A)) == exist(not(A)) > > Side channels, inference, and so on are deadly to theoretical > arguments about logical impossibility in real systems. Depends how you mean. If you're talking about, for example, the negation of Sassaman Conjecture, which negation amounts to "the maximal K for K-anonymity in a packet-switched network is >1," might be pretty straight-forward to falsify. There are giant socioeconomic issues rolled up in that seemingly abstruse question. Cheers, David. -- David Fetter <da...@fetter.org> http://fetter.org/ Phone: +1 415 235 3778 AIM: dfetter666 Yahoo!: dfetter Skype: davidfetter XMPP: david.fet...@gmail.com Remember to vote! Consider donating to Postgres: http://www.postgresql.org/about/donate _______________________________________________ langsec-discuss mailing list langsec-discuss@mail.langsec.org https://mail.langsec.org/cgi-bin/mailman/listinfo/langsec-discuss
