64-bit input 56bit key termite Symmetric Key L1 RI crypto: DES 48-bit KI fILL, RL, KID DES operation 12R2 initial permutation 48-bit K2 2R2K2 16 identical"rounds"of function application 13 each using different 48 bits of key final permutation 48-bit K16 t7R17 permu:e 64-bit output /: Network Security 107: Network Security 10 Symmetric key crypto: DES initial permutation 16 identical “rounds” of function application, each using different 48 bits of key final permutation DES operation