Novel Shuffling Countermeasure for Advanced Encryption Standard (AES) against Profiled Attack in Mobile Multimedia Services

Listing 1

Assembly code for the previous countermeasure [19].

1; OUT[ORD[i]] = Sbox[IN[ORD[i]]]

2 movw r28, r24

3 ldi  r26, 0x13

4 ldi  r27, 0x22

5 ldi  r20, 0x33

6 ldi  r21, 0x22

7 ld  r18, X+

8 ldi  r19, 0x00

9 movw r30, r28

10 add  r30, r18

11 adc  r31, r19

12 ld  r30, Z

13 ldi  r31, 0x00

14 subi r30, 0xF6

15 sbci r31, 0xDF

16 ld  r25, Z

17 movw r30, r22

18 add  r30, r18

19 adc  r31, r19

20 st  Z, r25