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 possible attacks on rsa encryption, Problem (a) Describe RSA a...

Problem (a) Describe RSA algorithm with an example. (b) Answer the following RSA encryption, given the values of the primes are: p = 17, q = 11 and choosing e = 7. (c)

Fragmentation, FRAGMENTATION One method is to limit datagram size to s...

FRAGMENTATION One method is to limit datagram size to smallest MTU of any server. IP needs fragmentation i.e. datagrams can be divided into pieces to fit in network with small

Define secure socket layer (ssl), Secure Socket Layer (SSL) accepts a combi...

Secure Socket Layer (SSL) accepts a combination of asymmetric and symmetric (public-key) encryption to accomplish integrity, confidentiality, authentication and non-repudiation for

CNSS, Assume that a security model is needed for the protection of informat...

Assume that a security model is needed for the protection of information in your class. Using the CNSS model, examine each of the cells and write a brief statement on how you would

Plaintext, how to encryt the data in plaintext cipher

how to encryt the data in plaintext cipher

Describe briefly an artificial intelligent technique, Question : (a) W...

Question : (a) What is an IDS and what is the basic problem it faces which can be solved by Artificial Intelligence. (b) Identify and describe briefly an Artificial Intell

Define network, A Network is described as a system for connecting compu...

A Network is described as a system for connecting computers using a single transmission technology. The computers can interact with each other in a network. They can receive an

Explain the three modes of vtp switches, QUESTION (a) What do you unde...

QUESTION (a) What do you understand by a VLAN? Provide one advantage of using a VLAN. (b) What is a trunk port in a VLAN? (c) A VLAN will be created using one or more

Why use an ids, WHY USE AN IDS? IDS prevent from problem behaviors by in...

WHY USE AN IDS? IDS prevent from problem behaviors by increasing the perceived risk of discovery and punishment. Detect the attacks and other security violations. Detect and at

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