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AES Guest Lecturer

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<strong>AES</strong> Algorithm<br />

Key Expansion<br />

For words 4 through 43<br />

i = N k // N k = 4<br />

while (i < N b *(N r +1)) {// N b *(N r +1)= 4*(10+1)= 44<br />

temp = W[i-1]<br />

If (i%N k == 0)<br />

i = 4<br />

rotate word left 1 byte<br />

process each byte through sbox<br />

XOR with RCON[i]<br />

w[i] = w[i-4] XOR ⨁ temp temp<br />

i++}<br />

temp // just = first C0 element 28 16 of w4B

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