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

Explain the term virtual private network, Question: (a) Besides privac...

Question: (a) Besides privacy, what other security functions does Pretty Good Privacy (PGP) provides? (b) What is the Post Office Protocol (POP) used for? Why is it impo

Placeholders for the plaintext characters, Encode the following plaintext, ...

Encode the following plaintext, using the Caesar cipher:             LORD OF THE RINGS b) The following ciphertext              jw njbh lxmn cx kanjt has been encoded usi

The effect the incident has on your business, QUESTION There are gener...

QUESTION There are generally five factors that will influence how you respond to computer security incidents- The effect the incident has on your business Legal issue

Develop a tcp-based client-server socket program, Develop a TCP-based clien...

Develop a TCP-based client-server socket program for transferring a large message. The message transmitted from the client to server is read from a large file (size is about 30000

Characteristics of radial basis function neural networks, Problem : (a)...

Problem : (a) Provide one possible classification of PCA, ART, RBF, and Fuzzy ARTMAP networks. (b) Describe in detail the characteristics of Radial Basis Function Neural Net

Analysis phase in the building-block approach, QUESTION: a) Explain fou...

QUESTION: a) Explain four issues that are generally addressed in the Needs Analysis phase in the building-block approach to network design. b) Sketch a typical hybrid star-b

Address resolution techniques, Address resolution algorithms may be grouped...

Address resolution algorithms may be grouped into three basic types: Table lookup Closed-form computation Message Exchange 1. TABLE LOOKUP: In Table Loo

Incident response, Incident Response: Complete the following sections as id...

Incident Response: Complete the following sections as identified from your Incident Response template (in MS Word format): Update the table of contents (autogenerated) Separate

Internet protocol (ipv6), SUCCESS OF IP:  IP has accommodated dramatic...

SUCCESS OF IP:  IP has accommodated dramatic modification since real design. But basic rules are still appropriate today. There are many new kinds of hardware. SCALING:

Functional areas in network management, Question 1 a) Explain how CSMA...

Question 1 a) Explain how CSMA/CD works. b) Describe the term "exponential back-off". c) Describe the differences between "circuit switching" and "packet switching". d) Th

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