2. Suppose you are developing an RSA public key encryption scheme. You decide to use the primes p 11 and q 19, and the semiprime n q = 209 as the modulus for the encryption/decryption (a) Show that e 7 is a valid public encryption key for this choice of p,q and n (b) Use e 7 as your public encryption key and p, q and n as above. Calculate the decryption key d. What is the smallest positive value you could use for d? Now, consider using p-11 and q 5, so n-55, with e-7 and d = 23, while not every calculation must be done by hand, your work should demonstrate use of the fast modular exponentiation (using binary representation of the exponents) that we talked about in class. (c) Encrypt the message "S EN D" (using single-letter blocks). (d) Decrypt the message "Y JARY" (24 09 00 17 24)