3. Hill cipher (a.) (4 points) How many different matrices A are there in modulo 2? How many of them are invertible? b.) (4 points) Suppose we know that the plaintext ABLE is encrypted as ZXTo using Hill cipher in modulo 26 with a matrix A. Find A. (c.) (7 points) Use the following letter-to-number conversion table 0 1 2 012 3456789 10 11 12 13 1415 1617 1819 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 to decrypt the following message knowing that it is the Hill cipher in modulo 37 and key matrix A cipher n modulo 37 and Key matrix /