The Encapsulating Security Payload (ESP) provides integrity and confidentiality for network communications.
ESP is a protocol that is part of the IPsec suite, which is a set of protocols and standards that provide security for Internet Protocol (IP) communications. ESP encrypts the payload of an IP packet, which is the data portion of the packet, to provide confidentiality. ESP also adds a trailer and an authentication data field to the packet, to provide integrity. ESP does not provide authorization or availability for network communications.
Authorization is the process of granting or denying access to resources based on the identity or role of the requester. Availability is the property of ensuring that resources are accessible and usable by authorized parties when needed. ESP does not perform authorization or availability functions, but it may support or complement them.

Because the Reference Monitor is responsible for access control to the objects by
the subjects it compares the security labels of a subject and an object.
According to the OIG: The reference monitor is an access control concept referring to an abstract
machine that mediates all accesses to objects by subjects based on information in an access
control database. The reference monitor must mediate all access, be protected from modification,
be verifiable as correct, and must always be invoked. The reference monitor, in accordance with
the security policy, controls the checks that are made in the access control database.
The following are incorrect:
Validation Module. A Validation Module is typically found in application source code and is used to
validate data being inputted.
Clearance Check. Is a distractor, there is no such thing other than what someone would do when
checking if someone is authorized to access a secure facility.
Security Module. Is typically a general purpose module that prerforms a variety of security related
functions.
References:
OIG CBK, Security Architecture and Design (page 324)
AIO, 4th Edition, Security Architecture and Design, pp 328-328.
Wikipedia - http://en.wikipedia.org/wiki/Reference_monitor

The National Commissioners on Uniform State Laws (NCUSL) voted to approve the Uniform Computers Information Transactions Act (UCITA) on July 29, 1999. This legislation, which will have to be enacted state-by-state, will greatly affect libraries access to and use of software packages. It also will keep in place the current licensing practices of software vendors. At the present time, shrink-wrap or click-wrap licenses limit rights that are normally granted under copyright law. Under Section 109 of the U.S. 1976 Copyright Act, the first sale provision permits the owner of a particular copy without the authority of the copyright owner, to sell or otherwise dispose of the possession of that copy. However, the software manufacturers use the term license in their transactions. As opposed to the word sale, the term license denotes that the software manufacturers are permitting users to use a copy of their softwarE . Thus, the software vendor still owns the softwarE . Until each state enacts the legislation, it is not clear if shrink-wrap licenses that restrict users rights under copyright law are legally enforceablE . For clarification, shrink-wrap licenses physically accompany a disk while click-on and active clickwrap licenses are usually transmitted electronically. Sometimes, the term shrink-wrap is interpreted to mean both physical and electronic licenses to use softwarE . The focus of the UCITA legislation is not on the physical media, but on the information contained on the media.

A stream cipher is a type of symmetric encryption algorithm that operates on continuous streams of plain text and is appropriate for hardware-based encryption.
Stream ciphers can be designed to be exceptionally fast, much faster than any block cipher. A stream cipher generates what is called a keystream (a sequence of bits used as a key).
Stream ciphers can be viewed as approximating the action of a proven unbreakable cipher, the one-time pad (OTP), sometimes known as the Vernam cipher. A one-time pad uses a keystream of completely random digits. The keystream is combined with the plaintext digits one at a time to form the ciphertext. This system was proved to be secure by Claude
Shannon in 1949. However, the keystream must be (at least) the same length as the plaintext, and generated completely at random. This makes the system very cumbersome to implement in practice, and as a result the one-time pad has not been widely used, except for the most critical applications.
A stream cipher makes use of a much smaller and more convenient key - 128 bits, for example. Based on this key, it generates a pseudorandom keystream which can be combined with the plaintext digits in a similar fashion to the one-time pad. However, this comes at a cost: because the keystream is now pseudorandom, and not truly random, the proof of security associated with the one-time pad no longer holds: it is quite possible for a stream cipher to be completely insecure if it is not implemented properly as we have seen with the Wired Equivalent Privacy (WEP) protocol.
Encryption is accomplished by combining the keystream with the plaintext, usually with the bitwise XOR operation.
Source: DUPUIS, Clement, CISSP Open Study Guide on domain 5, cryptography, April
1999.
More details can be obtained on Stream Ciphers in RSA Security's FAQ on Stream
Ciphers.

The correct answer is "An iterated block cipher". Answers A recursive, sequential cipher, A
Feistel network, and As treaming block cipher are distracters; however, answer A Feistel network characterizes the Data Encryption Standard (DES) cipher.