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

Spambot detection - spam mail, Spambot Detection: The  previous studie...

Spambot Detection: The  previous studies in this field  have focused on content and meta-content based features.  The main assumption in this area of spam detection of late is

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

Explain the architecture of ISDN.....?

Algorithm, algorithm on simple intrest

algorithm on simple intrest

Direct point-to-point communication:, Early networks used simple point-to...

Early networks used simple point-to-point communication . In such a method of communication every communication channel connects exactly two devices. In this way it prepares a m

Computer security, For this assessment, students must research and analyse ...

For this assessment, students must research and analyse two different scenarios. The two scenarios must be chosen from those described below and submitted as one Microsoft PowerPoi

Base lining-information security, Base lining •    Organizations do not ...

Base lining •    Organizations do not have any contact to each other •    No two organizations are identical to each other •    The best practices are a moving target •    K

Describe the procedure known as byte stuffing, Question: (a) For the b...

Question: (a) For the bit stream 010011, sketch the waveforms for each of the code indicated. Assume the following: the signal level for the previous bit for NRZI was a 1

Explain web defacement, QUESTION (a) Compare and contrast phishing and ...

QUESTION (a) Compare and contrast phishing and pharming attacks (b) Nowadays, web defacement may not always be visual (i) Explain web defacement (ii) What is the main

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