DES

 Data Encryption Standard (DES) was created in after a NIST issued RFP in 1973, which culminated in the winner “Lucifer”. Lucifer was modified by NSA to yield DES  Plaintext -> Initial Permutation -> 16 rounds -> final permutation ->Ciphertext  S-BOX: Confusion  P-BOX: Permutation 1

DES “Round”

L L’ 32 48 R 32 Expansion S-Box 32 P-Box R’ Key 52 shift shift Compression 48 Key’

PBOX

0: 16 1: 7 2: 20 3: 21 4: 29 5: 12 6: 28 7: 17 8: 1 9: 15 10: 23 11: 26 12: 5 13: 18 14: 31

SBOX

0: 14 1: 4 2: 13 3: 1 4: 2 5: 15 6: 11 7: 8 8: 3 9: 10 10: 6 11: 12 12: 5 13: 9 14: 0 2