The Basics of DES (cont’d)
How it works (in a nutshell)
- permute (shuffle) the 64 bits
- using the 56-bit key, take 16 different 48-bit subsets of the 56-bit key as “per-round” keys
- the input to each round is the output of the previous one, plus the 48-bit round key
- swap the two 32-bit halves, then permute them (inverse of initial permutation)
Details start on p. 372 in text