Communications and Networks Part 2

Question 1

A ________ is designed to protect a computer or network from intruders.

Answer 1

firewall

[Explanation]

A firewall can be hardware or software-based or a combination of the two.

Question 2

A _____ is a program that reproduces itself, either by making copies of itself or by attaching to another program.

Answer 2

virus

[Explanation]

Many common viruses attach themselves to an existing executable program, and when that program is copied to and run on other computers, the virus infects those computers.

Question 3

A ____________ is a program that is disguised as an innocent program to gain control of your computer.

Answer 3

Trojan horse

[Explanation]

Trojan horses refer to programs that appear to serve a normal function–i.e. two common examples are games and screensavers–but have a hidden, malicious agenda. For example, a game or a screensaver that’s a Trojan horse will contain code designed to give a hacker access to your computer. Trojan horses can also carry viruses and destructive instructions.

Question 4

__________ uses mathematical formulas to create coded messages.

Answer 4

Encryption

Question 5

To prevent unauthorized access to sensitive data, you encrypt data when you send it and this data is decrypted by its authorized recipient using an encryption ____.

Answer 5

key.

Question 6

___________ cable transmits pulsating beams of light rather than electricity.

Answer 6

Fiber optic

[Explanation]

Fiber optic cable consists of dozens or hundreds of thin strands of glass or plastic; it is more secure and can carry much more data than normal copper telephone wire.

Question 7

Infrared transmission sends data via light waves at a frequency too ___ for human eyes to see.

Answer 7

low

[Explanation]

Infrared ports can be found on some notebook computers, PDAs, mice and printers. Transmission is limited to short range.

Question 8

A message that has not been ________ is called plaintext.

Answer 8

encrypted

[Explanation]

Plaintext is also called cleartext.

Question 9

A message which has been encrypted is called __________.

Answer 9

cyphertext

Question 10

The process of converting cyphertext to plaintext is ________.

Answer 10

decryption

Question 11

Messages are encrypted using a cryptographic ________ and a key.

Answer 11

algorithm

[Explanation]

A cryptographic key is a number, word, or phrase that must be used to decrypt a message.

Question 12

An algorithm is a _______ or set of steps for solving a particular problem.

Answer 12

formula

[Explanation]

To be an algorithm, a set of rules must be unambiguous and have a clear stopping point.

Question 13

__________ encryption uses two keys.

Answer 13

Public key

[Explanation]

A public key is used to encrypt the message and a private key is used to decrypt it.

Public key encryption is used to transmit credit card data in secure e-commerce transactions and it is also used for secure email.

Question 14

The public key encryption software used to encrypt documents such as email is called ___.

Answer 14

PGP

[Explanation]

PGP (Pretty Good Privacy) encryption software is available for free download on the web.

Question 15

What does PGP stand for?

Answer 15

Pretty Good Privacy

Question 16

Passwords are often encrypted using a ____ function, which is a function that takes a string of characters of any length and converts it into a string of a specific length.

Answer 16

hash

[Explanation]

A hash function uses an algorithm to transform a given string of letters into a string that represents the original string (known as a hash). For instance, a common password hashing function will take any string, whether it be “b7b” or “sam@userexamplemail.com” and convert it into a 13 character string (for example, “e.lDRxlIpgM0G”).

Question 17

SSL and TLS are protocols used to _______ transmit credit card data over the Internet

Answer 17

securely

[Explanation]

SSL (Secure Socket Layer) and TLS are protocols used to create a secure connection between a computer and a website. Sensitive information such as credit card numbers is encrypted and therefore useless if intercepted.

Question 18

What does SSL stand for?

Answer 18

Secure Socket Layer

Question 19

__________ detection software is used by merchants for online transactions to detect and prevent fraud by establishing criteria each transaction must meet.

Answer 19

Rule-based

[Explanation]

Examples of rules this software would include are matching cardholder information such as billing and shipping address and checking the card number against a database of stolen credit card numbers.

Question 20

____ is the communications protocol used by your browser to connect with web servers and display web pages on your computer.

Answer 20

HTTP

[Explanation]

The web protocol HTTP (Hypertext Transfer Protocol) is a set of rules for exchanging information over the web.

Question 21

FTP is a protocol used to copy _____ from one computer to another over the Internet.

Answer 21

files

[Explanation]

FTP can be used on any TCP/IP network such as a LAN or the Internet and is compatible with any operating system.

Question 22

A ___ is a string of characters that points to a specific piece of information anywhere on the web.

Answer 22

URL

[Explanation]

Heres an example of a URL (Uniform Resource Locator):

http://www.degreeforum.net/general-education-testing-discussion/1-post-your-test-results.html.

Question 23

What does URL stand for?

Answer 23

Uniform Resource Locator

Question 24

What part of the URL http://instantcert.com/landing.html is the top level domain?

Answer 24

com

[Explanation]

Examples of common top level domains are com, edu, gov, info, mil, net, org, and biz. Notice that we are just talking about the top level domain. The domain name would be “instantcert.com”; the top level domain just refers to the part after the period.

Question 25

DHCP is a protocol designed to automatically __________ IP addresses.

Answer 25

distribute

Question 26

What does DHCP stand for?

Answer 26

Dynamic Host Configuration Protocol.

Question 27

An __________ is a series of numbers used to identify a network device.

Answer 27

IP address

[Explanation]

IP addresses are assigned to network devices, computers and peripherals. They can be changed by the network administrator.

Question 28

A MAC address is a series of numbers assigned by the manufacturer to a ___________ card at the factory.

Answer 28

network interface

[Explanation]

MAC addresses are used for network security and low level network functions. They are set from the factory and cannot be changed by the network admin.

Question 29

Packet switching technology divides a message into _______ that can be independently routed to their destination and then reassembled.

Answer 29

packets

[Explanation]

Messages are divided into equal size packets and shipped over the network on a first come first served basis.

Question 30

A ______ is a small unit of data transmitted over a network.

Answer 30

packet

[Explanation]

The TCP/IP protocol breaks data up into packets, which are fixed-length blocks of data, for transmission over the network. This permits the message to be broken up into small parts which are then transmitted over separate routes and yet all end up in the same place to be reassembled in the correct order.

Question 31

CSMA/CD is the Ethernet protocol that handles __________.

Answer 31

collisions

[Explanation]

When two stations transmit at the same time on a network, collisions occur. CSMA/CD manages collisions on the network by deleting colliding signals and resetting the network.