Recently there have been various reports in the press about weak RSA keys
iv One such report famously claims four keys in one thousand are useless. Obviously this would be a point of concern to ordinary users, but at the same time it wouldn’t necessarily be something they can easily verify.
No Such lAbs (MPEx :
S.NSA) makes it its business to mind security, and as such has recently released
Phuctor: The RSA Super Collider. Supercomputers running a highly advanced piece of algorithmics called EGCD
v are at your disposal, ready to help. All you have to do is paste your public key in and check back a little later. NSA will compare your public key to all the other keys already submitted and see if there’s any factors shared by at least two keys.
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iv. Keys which can be factorised fail to deliver on the original promise (that the problem is hard in one direction) and as such are pretty much useless. Or perhaps worse than useless, if anyone relies on them seriously.
v. Known ever since the ancient Greeks, inasmuch as it’s Euclid’s Greatest Common Divisor procedure.
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The full announcement and details are available
here.
