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

Information and network security, Information and Network Security Part ...

Information and Network Security Part 1- Recovery of an encrypted `word' using a forward search attack. Complete and correct summary for part 1. Adequately commented, clea

Provide a labelled drawing of a standard serial port, Question 1: (a) W...

Question 1: (a) With the help of a diagram show the basic structure of a computer system. (b) Explain as fully as you can each of the parts mentioned above. (c) What are

Caralouer case study: analysis and design techniques, CarALouer provides re...

CarALouer provides rental of cars to its customer on a regional basis i.e. a car is attached to a regional home-base which also houses a regional office of the company. Each regi

Negative cycle algorithm in minimum cost flows, QUESTION: (a) Show the...

QUESTION: (a) Show the Negative Cycle Algorithm in Minimum Cost Flows. (b) List the steps added in finding a Negative Cycle. (c) Apply Dijkstra's algorithm on the subs

Trap and trace systems-information security, TRAP AND TRACE SYSTEMS Trap...

TRAP AND TRACE SYSTEMS Trap and Trace Systems use techniques to detect an intrusion and trace it back to its source. Trap comprises of honey pot or padded cell and alarm. The dr

[email protected], Re: Website Google Ranking Hello! Hope yo...

Re: Website Google Ranking Hello! Hope you are doing well. I discovered some major issues in your website which might be the cause for the Google Penalties and poor search ranki

Write a note on digital signature, Question 1 Explain the types of threats...

Question 1 Explain the types of threats (Attacks) Question 2 What are the Characteristics of Good Encryption Technique? Question 3 Write a note on Digital Signatur

What are the ethical issues and implications, An injunction to 'think ethic...

An injunction to 'think ethically' about a situation is not helpful. Perhaps if one has a background in moral philosophy this would work, but usually both students and IT professio

Determine the round trip time, QUESTION a) Determine the RTT (round tr...

QUESTION a) Determine the RTT (round trip time) between a client requesting a web page of 1024 bytes in size from an internal web server on a 100 Base-T Ethernet. Consider a o

Arrangement of self-learning switches, QUESTION a) Consider the speed ...

QUESTION a) Consider the speed of propagation of an electrical signal is same to 2x10 8 m/s, evaluate the ratio of the propagation delay to the transmit time for the given typ

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