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

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

Structure of a typical frame relay, Problem a) Consider a 1000 Mbps Eth...

Problem a) Consider a 1000 Mbps Ethernet with a single Store-N-Forward switch mid-way in the path between two nodes A and B. Assume that there are no other nodes on the network

Draw the waveform for an asynchronous transmission, (a) Draw the waveform ...

(a) Draw the waveform for an asynchronous transmission with the given specifications: 8 data bits with value 11010001 (LSB listed first here), one parity bit (even), one star

Listing assets in order of importance-risk management, Listing Assets in Or...

Listing Assets in Order of Importance Weighting should be created for each category based on the answers to questions. The relative importance of each asset is calculated usin

Information asset classification-risk management, Information asset classif...

Information asset classification-risk management A number of organizations have data classification schemes (for instance confidential, internal, public data). The classificat

Plain-text using play-fair encryption, What is one-time pad for encryp...

What is one-time pad for encryption?  Describe how it offers both Confusion and Diffusion. Using the letter encoding discussed in class (along with one-time

CS, Discuss how developers should apply the following countermeasures to im...

Discuss how developers should apply the following countermeasures to improve the security of their code:

History, how did slavery influence life in the colonies

how did slavery influence life in the colonies

Classification of networks, Computer networks are defined by four factors w...

Computer networks are defined by four factors which are as given below: 1) NETWORK SIZE: According to the size of networks. 1) Local Area Network ( LAN) 2) Wide Area Ne

X.509, Consider the details of the X.509 certificate shown below. a. Identi...

Consider the details of the X.509 certificate shown below. a. Identify the key elements in this certificate, including the owner''s name and public key, its validity dates, the nam

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