### Cryptography: substitution-permutation network

Consider the following 2x2 s-box x | S(x) ---|------- 0 | 3 1 | 1 2 | 0 3 | 2 Consider 2-round SPN (substitution-permutation network) with a block length of 4 bits. If the key mixing is done using a mod-4 addition operation before each round and after the last round, determine the ciphertext corres