Caesar Cipher Basics Answers 1. What is the primary feature of the Caesar cipher? A. It employs a rotating key for encryption. B. It encrypts messages by reversing the order of letters. C. It utilizes complex mathematical algorithms. D. It involves shifting each letter of the alphabet a fixed number of positions. Answer: It involves shifting each letter of the alphabet a fixed number of positions. (D) The Caesar cipher is a straightforward substitution cipher that shifts letters a fixed number of positions. 2. What happens to the letter 'Z' when it is shifted by 3 positions? A. It becomes 'F'. B. It remains 'Z'. C. It becomes 'A'. D. It becomes 'C'. Answer: It becomes 'C'. (D) Shifting 'Z' by 3 positions results in 'C' due to wrapping around the alphabet. 3. Which of the following is true about the decryption process of the Caesar cipher? A. It uses a random key for every letter. B. It requires additional information not included in the ciphertext. C. It can only be performed using sophisticated software. D. It involves a negative shift of the key value. Answer: It involves a negative shift of the key value. (D) The decryption formula uses a negative shift of the key to decode the ciphertext. 4. What makes the Caesar cipher easy to decipher? A. The limited number of possible keys. B. The use of complex encryption methods. C. The randomization of letter positions. D. The requirement of a special key sharing method. Answer: The limited number of possible keys. (A) The Caesar cipher has only 26 possible keys, making it vulnerable to brute-force attacks. 5. Which letters are the most frequent in the English language that could affect frequency analysis of the Caesar cipher? A. Z, Y, X, W B. Q, R, S, T C. M, N, O, P D. E, T, A, O Answer: E, T, A, O (D) The letters E, T, A, and O are among the most common, impacting frequency analysis results. 6. Why is the Caesar cipher considered insecure by modern standards? A. It can be broken easily with frequency analysis. B. It employs a single usage key. C. It uses a variable algorithm for each letter. D. It relies on extensive computational power. Answer: It can be broken easily with frequency analysis. (A) Its simplicity and vulnerability to frequency analysis render the Caesar cipher highly insecure. 7. How does a negative shift affect the letters in the Caesar cipher? A. Letters are reversed entirely. B. Letters shift in their original positions. C. Letters are shifted to the left in the alphabet. D. Letters become scrambled unpredictably. Answer: Letters are shifted to the left in the alphabet. (C) A negative shift in the Caesar cipher means that letters are shifted leftward in the alphabet. 8. Which phrase best captures a limitation of the Caesar cipher? A. It has an excessive number of possible keys. B. It requires a complex key management system. C. It has a small key space, making it vulnerable. D. It is impractical for everyday communication. Answer: It has a small key space, making it vulnerable. (C) Due to only having 26 possible keys, the Caesar cipher has a small key space which leads to its vulnerability.