1. Write short description about MixColumns() transformation that constitutes the third transformation in each round of AES. Explain with an example. 2. How many words of the key metrics are used for...

1. Write short description about MixColumns() transformation that constitutes the third transformation in each round of AES. Explain with an example.

2. How many words of the key metrics are used for key expansion algorithm and how many words are generated from it in total?

3. Let us consider the first four words of the key schedule are w0, w1, w2, w3. From this, how do we need to obtain the next four words w4, w5, w6, w7?