What if we were to use DES in the following way: for a given text
x and key
k we would perform
k' is the complementary of
If an adversary has a few texts and their cipher-texts would he still need to run DES twice in each of the
2^56 rounds yielding a total of
2^57 rounds of encryption ?
Because if the opponent can't choose his texts then the complementary attribute of DES would not assist us in any way.
So would this type of encryption be similar in its strength to
2DES with 2 different keys since
2DES is also
2^57 runs (meet in the middle) ?
Or is there a smarter way ?