(a) How many different shift transformations are there with an N-letter alphabet.

(b)Find the formula for the number of different affine enciphering transformations there are with a N-letter alphabet.

(c) How many affine transformations are there when N=26,27,29,30.

(d) You intercept the cipher text "OFJDFOHFXOL" which was enciphered using an affine transformation of single-letter plaintext units in the 27 letter alphabet. You know that the first word is "I"("I" followed by blank) .Determine the enciphering key , and read the message.