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

Maximum transmission unit (mtu), Maximum Transmission Unit  (MTU) Eac...

Maximum Transmission Unit  (MTU) Each hardware method specification adds the definition of the maximum size of the frame data area, which is known the Maximum Transmission Uni

What is a firewall, QUESTION (a) Define and distinguish between Electro...

QUESTION (a) Define and distinguish between Electronic Commerce and Electronic Business (b) According to you what are the benefits that Electronic Commerce can brings to org

Logic bombs - attacks information security, Example 3: Logic bombs In th...

Example 3: Logic bombs In the year 2000, Timothy Lloyd was found responsible of causing $10 million and $12 million of damage to Omega Engineering, an American company specializ

Business needs-information security, BUSINESS NEEDS Information security...

BUSINESS NEEDS Information security performs four main functions for an organization. 1. Protects the ability of organization to function. 2. Enables safe operation of applicat

Compare the suitability and properties of isdn and adsl, Question : An a...

Question : An aircraft manufacturing company is considering linking the network of one of its offices to the network of its Headquarter using either xDSL or ISDN. i. Compare

ISDN, Explain the architecture of ISDN.....?

Explain the architecture of ISDN.....?

Explain the encryption model or symmetric cipher model, With explain the en...

With explain the encryption model the help of diagram. Symmetric cipher model uses the secret-key or a single-key for encryption/decryption purposes. It employs a symmetric encr

Network security keys, The three primary types of network protection are th...

The three primary types of network protection are the same as the three primary areas where a network can be attacked. Every network needs protection against people-related, hardwa

Describe header fields present in a udp segment, Question (a) In relati...

Question (a) In relation to a TCP segment structure, provide the fields responsible for: i. Connection Management ii. Flow Control iii. Error Control iv. Reliable, in-order

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