Explanation/Reference:
Once an identity is established it must be authenticated. There exist numerous technologies and implementation of authentication methods however they almost all fall under three major areas.
There are three fundamental types of authentication:
Authentication by knowledge-something a person knows
Authentication by possession-something a person has
Authentication by characteristic-something a person is
Logical controls related to these types are called "factors."
Something you know can be a password or PIN, something you have can be a token fob or smart card, and something you are is usually some form of biometrics.
Single-factor authentication is the employment of one of these factors, two-factor authentication is using two of the three factors, and three-factor authentication is the combination of all three factors.
The general term for the use of more than one factor during authentication is multifactor authentication or strong authentication.
Reference(s) used for this question:
Hernandez CISSP, Steven (2012-12-21). Official (ISC)2 Guide to the CISSP CBK, Third Edition ((ISC)2 Press) (Kindle Locations 2367-2379). Auerbach Publications. Kindle Edition.

When we encrypt data we are basically taking the plaintext information and applying some key material or keystream and conducting something called an XOR or Exclusive-OR operation.
The symbol used for XOR is the following: This is a type of cipher known as a stream cipher.
The operation looks like this: 0101 0001 Plain text 0111 0011 Key stream 0010 0010 Output (ciphertext)
As you can see, it's not simple addition and the XOR Operation uses something called a truth table that explains why 0+1=1 and 1+1=0.
The rules are simples, if both bits are the same the result is zero, if both bits are not the same the result is one.
The following answers are incorrect:
-Bit Swapping: Incorrect. This isn't a known cryptographic operations.
-Logical NOR: Sorry, this isn't correct but is where only 0+0=1. All other combinations of 1+1, 1+0 equals 0. More on NOR here.
-Decryption: Sorry, this is the opposite of the process of encryption or, the process of applying the keystream to the plaintext to get the resulting encrypted text.
The following reference(s) was used to create this question:
For more details on XOR and all other questions of cryptography. Subscribe to our holistic Security+ CBT tutorial at http://www.cccure.tv and http://en.wikipedia.org/wiki/Exclusive-or and http://en.wikipedia.org/wiki/Stream_cipher

Section: Security Operation Adimnistration
Explanation/Reference:
Change control sub-phase includes Recreating and analyzing the problem, Determining the interface that is presented to the user, and Establishing the priorities of requests.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 7: Applications and Systems Development (page 252).

Simple Mail Transfer Protocol (SMTP) is a protocol for sending e-mail messages between servers. POP is a protocol used to retrieve e-mail from a mail server. NFS is a TCP/IP client/server application developed by Sun that enables different types of file systems to interoperate regardless of operating system or network architecture. FTP is the protocol that is used to facilitate file transfer between two machines.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 88.

Section: Analysis and Monitoring
Explanation/Reference:
Tripwire is an integrity checking product, triggering alarms when important files (e.g. system or configuration files) are modified.
This is a tool that is not likely to be used by hackers, other than for studying its workings in order to circumvent it.
Other programs are password-cracking programs and are likely to be used by security administrators as well as by hackers. More info regarding Tripwire available on the Tripwire, Inc. Web Site.
NOTE:
The biggest competitor to the commercial version of Tripwire is the freeware version of Tripwire. You can get the Open Source version of Tripwire at the following URL: http://sourceforge.net/projects/tripwire/