In each round of DES, we have all components defined in Figure 31.8 in the text. Which components use a key and which components do not?

Figure 31.8

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4 2. 3. Straight permutation Compression permutation Expansion permutation Transposition n bits n bits b7|b6 bs|b4|b3|b2|b1|bo ... A predefined Key (n bits) function Shift left (3 bits) bab3 b2b bolb7 b6 b5 m bits n bits Substitution Exclusive-OR Shift b7 b6 bs b4 b3 b2 b1 bo b7 b6 bs b4 b3 b2 bi bo b7 be bs ba b3|b2b||bo b3 b2 bbob7 b6 bs b4 b7 b6 bs b4 b3 b2b1 bo b7 b6 bs b4 b3 b2 bi bo Swap Split Combine nナ サー M一