Let ENC and DEC be cipher encryption and decryption steps, not necessarily respectively. Consider the operation
c=ENC(k,p) c'=c XOR mask p'=DEC(k,c')
or the operation
c=ENC(k,p) k'=k XOR mask p'=DEC(k',c)
where c
, p
, c'
, p'
,
and mask
are all known. Can k
be
recovered with enough examples?
This is named after many Rubik's cube operations are of the form AXA-1; that is, first do a preparation, then do something, then undo the preparation.
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