Answer Happy

a) Alice is communicating with Bob using the RSA algorithm. Bob's public key is the pair (n=138028476135007, e=97). Alice has sent the binary ciphertext 01100001011111000011111100000110100110101011111 to Bob. You have intercepted this message. Decrypt it and give it as plain text in English. Clearly explain your answer. b) Use Bob's public key to send him the message “Bye” as a binary ciphertext.

c) One student claims to have invented a new security protocol. Given a hash function H, a symmetric encryption key algorithm E, and two secret keys Kį and K, known only to the sender and receiver, the sender converts a message m into the message c= H(K2 * m)), where * denotes concatenation. Can this protocol guarantee i) confidentiality? Ex, (m * ii) non-repudiation? iii) data integrity?