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

Reason for multiple topologies, REASON FOR MULTIPLE TOPOLOGIES Every t...

REASON FOR MULTIPLE TOPOLOGIES Every topology has disadvantages and advantages, which are described below: IN A RING:  It is simple to coordinate access to other dev

State the fermat-euler theorem, Question: (a) Prove that every positive...

Question: (a) Prove that every positive integer n can be factorized into a product of prime powers. (b) State the Fermat-Euler theorem as needed in the RSA system. (c) Us

Miss, You are an IT Security administrator in a banking organization. Your ...

You are an IT Security administrator in a banking organization. Your organization hired an outside IT firm to do a proof of Concept for new equipment which is a computer based syst

Describe how access control is implemented, Question: (a) How can you ...

Question: (a) How can you prevent someone from accessing your computer when you leave your office for some time? (b) What is the difference between a classic login and a w

Sequential label and supply, What questions should Iris ask Charlie about t...

What questions should Iris ask Charlie about the new job, about Kelvin''s team, and about the future of the company?

Describe the process of components identification, Probelm 1: Give the ...

Probelm 1: Give the History and Evolution of Wireless Communication System. Complete explanation Probelm 2: Describe the process of Components Identification and cal

Need assignemnt help in information security assignemnt, Need Assignemnt he...

Need Assignemnt help in Information security assignemnt

Explain how the diffie-hellman key agreement protocol works, (a) Using Fer...

(a) Using Fermat's theorem, find 3 201 mod 11. (b) Explain how the Diffie-Hellman key agreement protocol works and what its purpose and main properties are. Consider a Dif

Ucsf medical center case study-information security, Example : UCSF Medical...

Example : UCSF Medical Center In the year 2002, the University of California, San Francisco (UCSF) Medical Center received an email message from someone who claimed to be a doct

Example of a public key algorithm, Question : (a) There are two approa...

Question : (a) There are two approaches for providing confidentiality for packets in a network using symmetric encryption: End-to-End Encryption and Link Encryption. State wh

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