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

Hybrid cryptography systems-cryptography, Hybrid Cryptography Systems Th...

Hybrid Cryptography Systems This makes use of different cryptography systems. Except digital certificates, pure asymmetric key encryption is not used extensively. Asymmetric enc

Explain the main stages in the penetration testing process, Question: (...

Question: (a) i. Explain what is meant by Discretionary Access Control and Mandatory Access Control ii. Which method would be the most effective to ensure that users do

Direct indexing, DIRECT INDEXING It is less usually known method. It i...

DIRECT INDEXING It is less usually known method. It is possible only is cases where protocols address are given from a compact range. In the diagram below an example of direct

What is the major security flaw of set, QUESTION (a) Discuss why it is ...

QUESTION (a) Discuss why it is considered more secure to use the SET (Secure Electronic Transaction) for e-commerce instead of using SSL (b) Describe how the dual signature

History, how did slavery influence life in the colonies

how did slavery influence life in the colonies

Electronic mail, Electronic Mail: Electronic mail which is famous as e-...

Electronic Mail: Electronic mail which is famous as e-mail, as it is known to its number of users, has been around for more than two decades. Before 1990, it was mainly used in

ITC 571 Emerging Technologies and Innovation Assignment, Ask quProject brie...

Ask quProject brief template The project brief is a document upon which the full Project Proposal and Plan will be based. About me: Who are you? What do you do? What is your Exper

Digital certificates, A Certificate presents an organization in an official...

A Certificate presents an organization in an official digital form. This is same to an electronic identity card which serves the purpose of Identifying the owner of the certificate

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

Need Assignemnt help in Information security assignemnt

Function of key secrecy and algorithm secrecy in security, What is the func...

What is the function of key secrecy and algorithm secrecy in security?  Algorithm Secrecy is explained as follows: ‘Algorithm secrecy’ is a method of keeping an algorithm

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