Truncated and higher-order differential cryptanalysis

[ciphergoth]

turned out to be much less difficult than I feared. Truncated just means you consider sets of differentials of the form a -> b, where a is fixed but b can be any member of a set S; subkeys that suggest any b in S get their counters incremented. Higher-order just means you consider differences in differences; some functions have no good differential characteristics but excellent higher-order differential characteristics.

And it was the fact that I still didn't understand these two after all these years that was a big part of me getting depressed on the train back from Leuven!

Right, now to see if I can find a copy of the paper on differential-linear cryptanalysis. I think it's just a kind of truncated differential cryptanalysis where S is the set of texts that meet some affine constraint.

Hey, if duranorak can post incomprehensible things I don't see why I shouldn't :-)

Comments

[duranorak.livejournal.com]

I know I should be apologising, but the image of all you poor things actually trying to understand what I'm saying is making me laugh too much...

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[ciphergoth.livejournal.com]

Yeah, well I only have to think of you reading "Bias in the LEVIATHAN Stream Cipher"...

[duranorak.livejournal.com]

~g~ Only because I had nothing better to do with my afternoon...really...

Um. I didn't need to understand it. It was just that you had written it.

~wince~ I'm posting that, aren't I? Ack.

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