CISSP – Information Systems Security Architecture Professional (ISSAP) — Question 25

Which of the following statements about a stream cipher are true? Each correct answer represents a complete solution. Choose three.

Answer options

• A. It typically executes at a higher speed than a block cipher.
• B. It divides a message into blocks for processing.
• C. It typically executes at a slower speed than a block cipher.
• D. It divides a message into bits for processing.
• E. It is a symmetric key cipher.

Correct answer: A, D, E

Explanation

Answer A is correct because stream ciphers are designed for high-speed encryption. Answer D is also correct, as stream ciphers process data one bit at a time instead of in blocks. Answer E is accurate because stream ciphers use the same key for both encryption and decryption. Answers B and C are incorrect because stream ciphers do not divide messages into blocks and they typically operate faster than block ciphers.