ROUND TRANSFORMATION

• Each round consists of 4 steps

  • Step 1: ByteSub Transformation (Confusion)
  • Step 2: ShiftRow Transformation (Diffusion)
  • Step 3: MixColumn Transformation (Diffusion)
  • Step 4: Round Key Addition

• Final round slightly different from other rounds

ByteSub (State)

MixColumn (State)

ShiftRow (State)

Round Key Addition

(State, Round Key)

• Decryption
  • Steps executed in reverse order using inverse functions
  • Key schedule must be modified as well

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