CompTIA Security Plus Mock Test Q1047

Which of the following would provide the STRONGEST encryption?

A. Random one-time pad
B. DES with a 56-bit key
C. AES with a 256-bit key
D. RSA with a 1024-bit key


Correct Answer: A
Section: Cryptography

Explanation:
One-time pads are the only truly completely secure cryptographic implementations.
They are so secure for two reasons. First, they use a key that is as long as a plaintext message. That means there is no pattern in the key application for an attacker to use. Also, onetime
pad keys are used only once and then discarded. So even if you could break a one-time pad cipher, that same key would never be used again, so knowledge of the key would be
useless.

Incorrect Answers:
B, C, D: DES; AES, and RSA are less secure than one-time pads.

References:
Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis, 2014, pp. 250, 251, 252