Advanced Encryption Standard (AES) involves multiple rounds and each round in tu
ID: 3576374 • Letter: A
Question
Advanced Encryption Standard (AES) involves multiple rounds and each round in turn involves four different steps, including the “Byte substitution” step. Describe briefly the computations performed in this step. For AES-128, block size is 128-bit and its state is represented as 4x4 array of 8-bit bytes as shown below:
b0
b4
b8
b12
b1
b5
b9
b13
b2
b6
b10
b14
b3
b7
b11
b15
If this state vector at the beginning of some round is the following 128-bit or 16-byte number.
0x00
0x14
0x28
0x3b
0x 01
0x15
0x29
0x3c
0x02
0x16
0x2a
0x3d
0x03
0x17
0x3a
0x3e
“Using the slides used in the class, compute the value of state bytes (i.e., new bi’s) after the byte substitution step.
b0
b4
b8
b12
b1
b5
b9
b13
b2
b6
b10
b14
b3
b7
b11
b15
Explanation / Answer
AES is found at least six time faster than triple DES. It has following features !
Chegg policy breaking sentence: “Using the slides used in the class, compute the value of state bytes (i.e., new bi’s) after the byte substitution step.
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