Quiz 1 Preparation

Answer all questions. Explain your answer in detail

• Question 1 (5 points): Calculate and explain your calculations:

  -34 % 7 =

• Question 2 (19 points): Encrypt the plaintext today with shift cipher with key = 13. Explain ONE letter in detail showing ALL calculations.

• Question 3 (19 points): Decrypt the message JDPH that was encrypted with Caesar Cipher. Explain ONE letter in detail showing ALL calculations.

• Question 4 (19 points): Decrypt the message "KTBG" that was encrypted with shift cipher. What is the key that was used in the shift encryption formula? You can use applet to perform calculations. You final answer must include the original plaintext and the KEY.

• Question 5 (19 points): Encrypt the message "good" with Affine Cipher C = P*3 + 7 (mod 26). Explain ONE letter in detail showing all calculations.

• Question 6 (19 points): Decrypt the message "HEAWPCCK" that was encrypted with Affine Cipher C = (P*11 + 4)(mod 26). Write the decryption formula (you don't need to show how to find multiplicative inverse, you can use the table we created in class). Explain ONE letter in detail showing all calculations. What condition multiplicative inverse must satisfy?