Sunday, October 18, 2009

SY0-201 Practice Exam Question Cryptography

Which of the following can use a PSK?

  A. Asymmetric encryption

  B. PKI

  C. TPM

  D. PGP

Answer below.
On the surface, this 8 word question seems rather simplistic. However, unless you've spent time with the material, all of the acronyms will make it very difficult. PSK can mean many things, but in the context of  security, and with all of the answers relating to cryptography, it refers to a pre-shared key.

Over 375 practice test questions in this book:
CompTIA Security+: Get Certified Get Ahead: SY0-201 Study Guide

The correct answer is C. A trusted platform module (TPM) uses a pre-shared key (PSK) to encrypt and decrypt data such as entire disks.  (Microsoft uses this with BitLocker.) Symmetric encryption uses a single key to both encrypt and decrypt while asymmetric encryption uses two keys—public and private. Both PGP (Pretty Good Privacy) and PKI (Public Key Infrastructure) use asymmetric encryption.

Good luck on the exam.

Darril Gibson