OKullmann/oklibrary — pull request #329 by MGwynne (2012-01-11 14:59:22+00:00)
Title: Number of solutions for DES instances.

Branch: des_num_solutions.

For rounds 1 to 3, there are multiple keys which maps some plaintexts to some ciphertexts,
and the number of such keys seems to decrease as the number of rounds
increases. For round 4, there seem to be only one ("true"/56-bit) key that maps each pair.

Matthew