Step 3d: S-box substitution (con’t)

• Replace the 6 data bits with the 4-bit S-box value

  • S1 box:
    14 4 13 1 2 15 11 8 3 10 6 12 5 9 0 7
    0 15 7 4 14 2 13 1 10 6 12 11 9 5 3 8
    4 1 14 8 13 6 2 11 15 12 9 7 3 10 5 0
    15 12 8 2 4 9 1 7 5 11 3 14 10 0 6 13

• K1 ? E(R0) = 011000 010001 011110 111010 100001 100110 010100 100111

  • Row address is 00
  • Column address is 1100
  • S1(B1) = 5 = 0101

• Example: S(B) = 0101 1100 1000 0010 1011 0101 1001 0111

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