A security domain is a domain of trust that shares a single security policy and single management.
The term security domain just builds upon the definition of domain by adding the fact that resources within this logical structure (domain) are working under the same security policy and managed by the same group.
So, a network administrator may put all of the accounting personnel, computers, and network resources in Domain 1 and all of the management personnel, computers, and network resources in Domain 2. These items fall into these individual containers because they not only carry out similar types of business functions, but also, and more importantly, have the same type of trust level. It is this common trust level that allows entities to be managed by one single security policy.
The different domains are separated by logical boundaries, such as firewalls with ACLs, directory services making access decisions, and objects that have their own ACLs indicating which individuals and groups can carry out operations on them.
All of these security mechanisms are examples of components that enforce the security policy for each domain. Domains can be architected in a hierarchical manner that dictates the relationship between the different domains and the ways in which subjects within the different domains can communicate. Subjects can access resources in domains of equal or lower trust levels.
The following are incorrect answers:
The reference monitor is an abstract machine which must mediate all access to subjects to objects, be protected from modification, be verifiable as correct, and is always invoked. Concept that defines a set of design requirements of a reference validation mechanism (security kernel), which enforces an access control policy over subjects' (processes, users) ability to perform operations (read, write, execute) on objects (files, resources) on a system. The reference monitor components must be small enough to test properly and be tamperproof.
The security kernel is the hardware, firmware and software elements of a trusted computing base that implement the reference monitor concept.
The security perimeter includes the security kernel as well as other security-related system functions that are within the boundary of the trusted computing base. System elements that are outside of the security perimeter need not be trusted. not every process and resource falls within the TCB, so some of these components fall outside of an imaginary boundary referred to as the security perimeter. A security perimeter is a boundary that divides the trusted from the untrusted. For the system to stay in a secure and trusted state, precise communication standards must be developed to ensure that when a component within the TCB needs to communicate with a component outside the TCB, the communication cannot expose the system to unexpected security compromises. This type of communication is handled and controlled through interfaces.
Reference(s) used for this question:
Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (Kindle Locations 28548-28550). McGraw-Hill. Kindle Edition.
Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (Kindle Locations 7873-7877). McGraw-Hill. Kindle Edition.
Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition , Access Control, Page 214-217
Schneiter, Andrew (2013-04-15). Official (ISC)2 Guide to the CISSP CBK, Third Edition :
Security Architecture and Design (Kindle Locations 1280-1283). . Kindle Edition.
TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.
AIO 6th edition chapter 3 access control page 214-217 defines Security domains.
Reference monitor, Security Kernel, and Security Parameter are defined in Chapter 4,
Security Architecture and Design.

Explanation/Reference:
DES works with 64 bit blocks of text using a 64 bit key (with 8 bits used for parity, so the effective key length is 56 bits).
Some people are getting the Key Size and the Block Size mixed up. The block size is usually a specific length. For example DES uses block size of 64 bits which results in 64 bits of encrypted data for each block. AES uses a block size of 128 bits, the block size on AES can only be 128 as per the published standard FIPS-197.
A DES key consists of 64 binary digits ("0"s or "1"s) of which 56 bits are randomly generated and used directly by the algorithm. The other 8 bits, which are not used by the algorithm, may be used for error detection. The 8 error detecting bits are set to make the parity of each 8-bit byte of the key odd, i.e., there is an odd number of "1"s in each 8-bit byte1. Authorized users of encrypted computer data must have the key that was used to encipher the data in order to decrypt it.
IN CONTRAST WITH AES
The input and output for the AES algorithm each consist of sequences of 128 bits (digits with values of 0 or
1). These sequences will sometimes be referred to as blocks and the number of bits they contain will be referred to as their length. The Cipher Key for the AES algorithm is a sequence of 128, 192 or 256 bits.
Other input, output and Cipher Key lengths are not permitted by this standard.
The Advanced Encryption Standard (AES) specifies the Rijndael algorithm, a symmetric block cipher that can process data blocks of 128 bits, using cipher keys with lengths of 128, 192, and 256 bits. Rijndael was designed to handle additional block sizes and key lengths, however they are not adopted in the AES standard.
The AES algorithm may be used with the three different key lengths indicated above, and therefore these different "flavors" may be referred to as "AES-128", "AES-192", and "AES-256".
The other answers are not correct because:
"64 bits of data input results in 56 bits of encrypted output" is incorrect because while DES does work with
64 bit block input, it results in 64 bit blocks of encrypted output.
"128 bit key with 8 bits used for parity" is incorrect because DES does not ever use a 128 bit key.
"56 bits of data input results in 56 bits of encrypted output" is incorrect because DES always works with 64 bit blocks of input/output, not 56 bits.
Reference(s) used for this question:
Official ISC2 Guide to the CISSP CBK, Second Edition, page: 336-343
http://csrc.nist.gov/publications/fips/fips197/fips-197.pdf
http://csrc.nist.gov/publications/fips/fips46-3/fips46-3.pdf

Explanation/Reference:
Detective/Technical measures include intrusion detection systems and automatically-generated violation reports from audit trail information. These reports can indicate variations from "normal" operation or detect known signatures of unauthorized access episodes. In order to limit the amount of audit information flagged and reported by automated violation analysis and reporting mechanisms, clipping levels can be set.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 35.

Section: Network and Telecommunications
Explanation/Reference:
The main characteristic of a multi-homed host is that is has multiple network interfaces, each connected to logically and physically separate networks. IP routing should be disabled to prevent the firewall from routing packets directly from one interface to the other.
Source: FERREL, Robert G, Questions and Answers for the CISSP Exam, domain 2 (derived from the Information Security Management Handbook, 4th Ed., by Tipton & Krause).

Even thou all 4 terms are very close to each other, the best choice is Excessive Privileges which would include the other three choices presented.
Reference(s) used for this question:
HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2001, Page 645. and