CompTIA Security Plus Mock Test Q1050

Sara, a security engineer, is testing encryption ciphers for performance. Which of the following ciphers offers strong encryption with the FASTEST speed?

A.
3DES
B. Blowfish
C. Serpent
D. AES256

Correct Answer: B
Section: Cryptography

Explanation:
Blowfish is an encryption system invented by a team led by Bruce Schneier that performs a 64-bit block cipher at very fast speeds. Blowfish is a fast, except when changing keys. It is a
symmetric block cipher that can use variable-length keys (from 32 bits to 448 bits).

Incorrect Answers:
A: 3DES would be slower than Blowfish.
Triple-DES (3DES) is a technological upgrade of DES. 3DES is still used, even though AES is the preferred choice for government applications. 3DES is considerably harder to break
than many other systems, and it’s more secure than DES. It increases the key length to 168 bits (using three 56-bit DES keys).
C: Serpent would be slower than Blowfish.
Serpent is a symmetric key block cipher that has a block size of 128 bits and supports a key size of 128, 192 or 256 bits.
D: AES256 (also often written as AES-256) uses 256 bits instead of 128. This qualifies for U.S. government classification as Top Secret. AES256 would be slower than Blowfish.

References:
Dulaney, Emmett and Chuck Eastton, CompTIA Security+ Study Guide, 6th Edition, Sybex, Indianapolis, 2014, pp. 250, 251, 255-256
http://en.wikipedia.org/wiki/Serpent_%28cipher%29