1.1. A financial advisor, Mr X, wants to send a protected trading document to his client, Mr Y. Mr.X wants to ensure that only Mr. Y can open the protected trading document and no one else, thus ensuring confidentiality through the use of PKI. Which key should Mr X use to send the protected trading document to Mr Y? (Select the correct answer and write down only the question number and the alphabetic letter as your answer.) (2) a) Mr Y's public key b) Mr Y's private key c) Mr Xs public key d) Mr Xs private key 1.2. Mr. x wants to ensure authenticity when sending the protected trading document to Mr. Y. Which key would Mr.X use? (Select the correct answer and write down only the question number the alphabetic letter as your answer.) a) Mr Y's public key b) MrY's private key c) Mr Xs public key d) Mr Xs private key (2) QUESTION 2 Consider the following plain text message: FOUR PM AT SMITH STR Encrypt the plain text message above using the two techniques as required by (a) and (b) respectively, one after the other: a) Use a Caesar Cipher with a shift of THREE, and then, b) encrypt the resulting ciphertext using a FOUR-column columnar transposition cipher Note that you must perform the Caesar Cipher on the message, then the columnar transposition on the cipher text that is produced from the operation of the Caesar Cipher.