Systems Security Certified Practitioner – SSCP – Question0688 - Systems Security Certified Practitioner

In a known plaintext attack, the cryptanalyst has knowledge of which of the following?

A. the ciphertext and the key
B. the plaintext and the secret key
C. both the plaintext and the associated ciphertext of several messages
D. the plaintext and the algorithm

Correct Answer: C

Explanation:

In a known plaintext attack, the attacker has the plaintext and ciphertext of one or more messages. The goal is to discover the key used to encrypt the messages so that other messages can be deciphered and read. Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 3rd Ed., chapter 8: Cryptography (page 676). Also check out: Handbook of Applied Cryptography 4th Edition by Alfred J. Menezes, Paul C. van Oorschot and Scott A. Vanstone.