Consider the following Sbox

Construct a $2-$ round SPN $($similar to the one presented in class$)$ with block length $4$ bits. If the

key mixing is done using XOR operation. Assume the round keys are $k_1=11,k_2=10,$ and $k_3=7.$

a$)$ Determine the ciphertext corresponding to $P_1=5$ and $P_2=12.$

b$)$ Repeat the above if the XOR operations in the key mixing is replaced by addition modulo