QUESTION: 21

Maria works as a Network Security Officer for Gentech Inc. She wants to encrypt her network traffic.

The specific requirement for the encryption algorithm is that it must be a symmetric key block cipher.
Which of the following techniques will she use to fulfill this requirement?

IDEA
PGP
DES
AES

Answer(s): C

Explanation:

The Data Encryption Standard (DES) is a block cipher (a form of shared secret encryption) that was selected by the National Bureau of Standards as an official Federal Information Processing Standard (FIPS) for the United States in 1976

and which has subsequently enjoyed widespread use internationally. It is based on a symmetric-key algorithm that uses a 56-bit key. The algorithm was initially controversial with classified design elements, a relatively short key length, and suspicions about a National Security Agency (NSA) backdoor. DES consequently came under intense academic scrutiny, which motivated the modern understanding of block ciphers and their cryptanalysis.

Reveal Solution Next Question

QUESTION: 22

Which of the following protocols uses public-key cryptography to authenticate the remote computer?

SSH
Telnet
SCP
SSL

Answer(s): A

Explanation:

Secure Shell (SSH) is a protocol that provides strong authentication and secure communications over unsecured channels. It uses public key encryption as the main method for user authentication. SSH secures connections over the Internet by encrypting passwords and other data.
It also protects networks against IP spoofing, packet spoofing, password sniffing, and eavesdropping.
SSH uses TCP port 22 as the default port and operates at the application layer.
SSH protocol has the following three components:
1.Transport layer protocol
2.User authentication protocol
3.Connection protocol
Answer option C is incorrect. The SCP protocol sends data in encrypted format. It is used to prevent potential packet sniffers from extracting usable information from data packets. The protocol itself does not provide authentication and security; it relies on the underlying protocol,
SSH, to provide these features. SCP can interactively request any passwords or passphrases required to make a connection to a remote host,

unlike rcp that fails in this situation.
The SCP protocol implements file transfers only. It does so by connecting to the host using SSH and there executes an SCP server (scp). The
SCP server program is typically the same program as the SCP client. Answer option D is incorrect. Secure Sockets Layer (SSL), also known as Transport Layer Security (TLS) are cryptographic protocols that provide security for communications over networks such as the Internet. TLS and SSL encrypt the segments of network connections at the
Transport Layer end-to-end. SSL uses a program layer located between the Internet's Hypertext Transfer Protocol (HTTP) and Transport
Control Protocol (TCP) layers.
Answer option B is incorrect. The full form of Telnet is Teletype Network. It is used to connect a computer to a local network (LAN) or the
Internet. It can also be used for accessing servers by using a valid user name and password. It is a common way to control Web servers remotely.