Explanation/Reference:
The primary objective of proper separation of duties is to ensure that one person acting alone cannot compromise the company's security in any way. A proper separation of duties does not prevent employees from disclosing information, nor does it ensure that access controls are in place or that audit trails are not tampered with.
Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, Chapter
12: Operations Security (Page 808).

Quench

Explanation/Reference:
It is a data integrity assurance software aimed at detecting and reporting accidental or malicious changes to data.
The following answers are incorrect :
Nessus is incorrect as it is a vulnerability scanner used by hackers in discovering vulnerabilities in a system.
Saint is also incorrect as it is also a network vulnerability scanner likely to be used by hackers.
Nmap is also incorrect as it is a port scanner for network exploration and likely to be used by hackers.
Reference :
Tripwire : http://www.tripwire.com
Nessus : http://www.nessus.org
Saint : http://www.saintcorporation.com/saint
Nmap : http://insecure.org/nmap

Section: Access Control
Explanation/Reference:
In 1973 Bell and LaPadula created the first mathematical model of a multi-level security system.
The following answers are incorrect:
Diffie and Hellman. This is incorrect because Diffie and Hellman was involved with cryptography.
Clark and Wilson. This is incorrect because Bell and LaPadula was the first model. The Clark-Wilson model came later, 1987.
Gasser and Lipner. This is incorrect, it is a distractor. Bell and LaPadula was the first model.

: . SATAN (an acronym standing for Security Administrator Tool for Analyzing Networks) is a testing and reporting tool that gathers information from networks, such as type of machine and security flaws that may be on these machines. SATAN was developed by Dan Farmer of Silicon Graphics with a purpose of scanning thousands of host computers on the Internet for security vulnerabilities. Availability: anonymous ftp at ftp.cerias.purdue.edu