Consider the following combination of Hill and Vigenre ciphers: The key consists of three 22matrices, M1, M2, M3. The plaintext letters are represented as integers mod 26. The first two are encrypted by M1, the next two by M2, the 5th and 6th by M3. This is repeated cyclically, as in the Vigenre cipher. Explain how to do a chosen plaintext attack on this system. Assume that you know that three 22 matrices are being used. State explicitly what plaintexts you would use and how you would use the outputs.