Section: Risk, Response and Recovery
Explanation/Reference:
The exposure factor is a measure of the magnitude of loss or impact on the value of an asset.
The probability is the chance or likelihood, in a finite sample, that an event will occur or that a specific loss value may be attained should the event occur.
A vulnerability is the absence or weakness of a risk-reducing safeguard.
A threat is event, the occurrence of which could have an undesired impact.
Source: ROTHKE, Ben, CISSP CBK Review presentation on domain 3, August 1999.

Section: Access Control
Explanation/Reference:
The ss (simple security) property of the Bell-LaPadula access control model states that reading of information by a subject at a lower sensitivity level from an object at a higher sensitivity level is not permitted (no read up).
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 5: Security Architectures and Models (page 202).

Explanation/Reference:
RC4 is a proprietary, variable-key-length stream cipher invented by Ron Rivest for RSA Data Security, Inc.
Skipjack, IDEA and Blowfish are examples of block ciphers.
Source: SHIREY, Robert W., RFC2828: Internet Security Glossary, may 2000.