Final answer:
In AES encryption, the S-Box is used to substitute input bytes with output bytes. The AES S-Box is a substitution table that replaces each input byte with a corresponding output byte, usually represented in hexadecimal format. (i) The corresponding output in hexadecimal format for the input 12310 in AES ByteSubstitute is 6C716. (ii) The corresponding input in hexadecimal format for the output 21310 in AES ByteSubstitute is 12316.
Step-by-step explanation:
In AES encryption, during the ByteSubstitute step, an S-Box is used to substitute one input byte with an output byte. The S-Box is a substitution table that replaces each input byte with a corresponding output byte. The S-Box is usually represented in hexadecimal format.
(i) To find the corresponding output in hexadecimal format for an input of 12310, we look up the value of 1 in the S-Box, which gives us the output 6. Next, we look up the value of 2 in the S-Box, which gives us the output C. Finally, we look up the value of 3 in the S-Box, which gives us the output 7. Therefore, the corresponding output in hexadecimal format for the input 12310 is 6C716.
(ii) To find the corresponding input in hexadecimal format for an output of 21310, we do the reverse process. We look for the output 2 in the S-Box, which gives us the input 1. Next, we look for the output 1 in the S-Box, which gives us the input 2. Finally, we look for the output 3 in the S-Box, which gives us the input 3. Therefore, the corresponding input in hexadecimal format for the output 21310 is 12316.