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

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:

Illustrate the label switching procedure in an mpls network, QUESTION ...

QUESTION a) Explain the terms traffic engineering, class-based queuing, shaping and grooming in an MPLS network. b) Using an example topology, illustrate the label swi

Distinguish between steganograhy and cryptography, Question: (a) Disti...

Question: (a) Distinguish between Steganograhy and Cryptography. (b) "Playfair cipher is more secure than Monoalphabetic cipher." Justify this statement. (c) Various ap

Evaluations, Evaluations, Assessment, and Maintenance of Risk Controls W...

Evaluations, Assessment, and Maintenance of Risk Controls When the control strategy has been implemented, it should be monitored and measured on an ongoing basis to determine ef

Tcp and udp, TCP and UDP End-to-end delivery application is connection...

TCP and UDP End-to-end delivery application is connection less. The basic function of connectionless service are as given: It adds extension of LAN abstraction. It has simp

Feasibility studies-risk management, Feasibility Studies Before deciding...

Feasibility Studies Before deciding on strategy, all information of economic or non economic consequences of vulnerability of information asset should be explored. A number of w

Explain quality management system, Question: Quality management standar...

Question: Quality management standards are seen as a major pillar supporting the drive for continuous quality improvement through TQM. (a) What do you meant by the term ‘Qua

Describe what the term session hijacking means, An overall rise in mobility...

An overall rise in mobility, coupled with the falling cost of Wi-Fi equipment, has led to a proliferation of Wi-Fi hot spots in public areas to provide Internet accessibility. Thus

Benchmarking-information security, Benchmarking An alternative approach to...

Benchmarking An alternative approach to risk management is Benchmarking. It is process of seeking out and studying practices in other organizations which one’s own organization de

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