AES Algorithm: State Block Representation & S-box Transformation

The size of the State block is 4x4, meaning it has 4 rows and 4 columns. To apply the AES S-box transformation, we need to substitute each byte of the State block with a new byte obtained from a lookup table.

The AES S-box lookup table is a 16x16 table that maps each possible byte value to a new byte value. To apply the transformation, we need to split each byte in the State block into two parts: the first four bits and the last four bits. We then use these two parts as indices to look up the corresponding new byte value from the AES S-box table.

For example, let's take the first byte in the State block: 'D1'. We split it into two parts: 'D' (1101 in binary) and '1' (0001 in binary). We use these two parts as indices to look up the new byte value from the AES S-box table. In this case, the new byte value is '84'.

We repeat this process for each byte in the State block, and we obtain the following new State block:

'84 7C 1B FE' '3A 0C A8 42' 'FD C7 47 11' '51 D6 98 EC'

So the new State block after applying the AES S-box transformation is:

'84 3A FD 51' '7C 0C C7 D6' '1B A8 47 98' 'FE 42 11 EC'