ciphertext, Computer Network Security

Assignment Help:
Encode the following plaintext, using the Caesar cipher:

LORD OF THE RINGS
b) The following ciphertext

jw njbh lxmn cx kanjt

has been encoded using a generalised Caesar cipher where the following rule computes a character ci in the cipher text from a character pi in the plain text:

ci = E(pi) = pi + d

where d is a positive integer.

Find the number d and the plain text. Hint: use a table of English letter frequencies. This information can be found on the Internet.

c) Now consider the following cipher text:

homlox prv hetorx orxolxpersorx

A more general substitution cipher has been used. Recall that this means that every letter of the alphabet appearing in the plain text is replaced with another unique letter of the alphabet. For example, the letter ''a'' could be mapped into ''h'', the letter ''b'' into ''x'' etc. The ciphertext then simply consists of these mapped letters.
Work out the original plain text message, using the following approach:

(i) Write a line of dashes ("_") as placeholders for the plaintext characters corresponding to each letter in the above cipher text. Make sure you also mark the spaces between the different words as they will give you clues as soon as you know some of the letters.

(ii) Using the English letter frequency table, find the letter which the letter "e" is most likely to be replaced with. Use this to replace some of the "_" by the letter "e" (simply copy the last line you wrote and then replace).

Related Discussions:- ciphertext

History, how did slavery influence life in the colonies

how did slavery influence life in the colonies

Find the services implemented on your computer, Question: (a) Which typ...

Question: (a) Which type of attacker represents the most likely and most damaging risk to your network? (b) What is the basic reason that social engineering attacks succeed?

Develop a preliminary simulation model, Question: (a) State the strong ...

Question: (a) State the strong law of large numbers. (b) Data have been collected on response times (in minutes) at a fire station. The data are 2:7 1:8 0:8 1:4 1:2 (i

Network-based ids (nids), Network-Based IDS (NIDS) A NIDS resides on com...

Network-Based IDS (NIDS) A NIDS resides on computer or appliance connected to segment of an organization’s network and looks for signs of attacks. While examining packets, a NID

Evaluate the percentage availability of the network, QUESTION a) "Two ...

QUESTION a) "Two of the key attributes of an enterprise network is that it have to be multi-platform and multisite." Decribe what you understand by this statement. b) A

Ping command , In the early days when there were some dozen computers machi...

In the early days when there were some dozen computers machine on the network, it was done individually but now as we have looked that there are millions of computers on the intern

Enterprise information security policy (eisp), Enterprise Information Secur...

Enterprise Information Security Policy (EISP) EISP also known as security policy directly supports the mission of the organization and sets the strategic direction, scope, and t

Risk control strategies-, Risk Control Strategies Once the ranked vulner...

Risk Control Strategies Once the ranked vulnerability risk worksheet has created, they should choose one of following 4 strategies to control each risk: •Apply safeguards which

Computer security incident response team, QUESTION 1 Using a real life ...

QUESTION 1 Using a real life scenario or context list and set the scene for at least four advantages that an organized incident response program promotes. QUESTION 2 Yo

What is authentication? explain authentication protocols, What is Authentic...

What is Authentication/confirmation?  How it is different from  the Authorization/approval?  Explain in brief different authentication protocols along with their merits and demerit

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd