Understanding Cisco Cybersecurity Operations Fundamentals (CBROPS) — Question 69

Which attack is the network vulnerable to when a stream cipher like RC4 is used twice with the same key?

Answer options

• A. forgery attack
• B. plaintext-only attack
• C. ciphertext-only attack
• D. meet-in-the-middle attack

Correct answer: C

Explanation

Using a stream cipher like RC4 with the same key for two different streams can lead to a ciphertext-only attack, where an attacker can analyze the output to potentially recover the plaintext. The other attack types listed do not specifically take advantage of this key reuse scenario in the same way, making them less relevant in this context.