I'm currently studying AES encryption and I'm quite confused on how do we use a 256-bit key in AES?
Becuase in my understanding, AES no matter what the key size is, it still operates and encrypt a 128-bit block of message only in the whole cycle/rounds until it reaches the end.
well for AES-128 we use a 128-bit key that is total of 16 byte char, and that can be represented by a 4x4 matrix, and most AES operations and steps works on 4x4 matrix right?
Then how do we use a 256 bit key?, that is a 32 byte char and that is not even a perfect square right?
Will that 256-bit key result into the same size of 128-bit key version of AES when expanded by key expansion? and just use 16 bytes each when encrypting to match the 4x4 state array?