4. Key Schedule

• User can provide 128-bit, 192-bit or 256-bit key

• The six round key is computed from the user key

• Example: for 128-bit user key

User key :

K1

K2

RK1 = E(K1) RK4 = E(K2 xor ɚ> xor RK3)

RK2 = E(K2 xor RK1) RK5 = E(K1 xor ɜ> xor RK4)

RK3 = E(K1 xor ə>xor RK2) RK6 = E(K2 xor ɠ> xor RK5)

Round keys:

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