re s s in article r ue access digex net steve b access digex com steve brinich writes second question why why is such a strange procedure used and not a real rng this turns those s s in a kind of bottleneck for system security the only theory that makes any sense is that s and s are either the same for all chips or vary among very few possibilities so that anyone trying to break the encryption by brute force need only plow through the possible serial numbers about one billion multiplied by the number of different s s combinations suppose instead that s and s can be reconstructed given or of the unit keys generated in a single batch through some sort of known plaintext attack say suppose further that or of the chips programmed in each session never find their way into commercial products but instead end up elsewhere suppose the folks at elsewhere can determine a unit key given physical access to one of these chips then those same folks can determine s and s for the whole batch too many suppositions yeah probably pat
