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

Develop a completely secure wsn based on the triple key, Q. Develop a compl...

Q. Develop a completely secure WSN based on the triple key? Wireless network is the most vulnerable type of network to security attack. Unauthorized access to wireless network

What do you understand by demilitarized zone, Problem 1: What does the ...

Problem 1: What does the SNMP access policy show? SNMP community diagram SNMP access policy Problem 2: Does there exist any formal functional specificat

Explain symmetric and asymmetric encryption system, Question 1: (a) Dif...

Question 1: (a) Differentiate between symmetric and asymmetric encryption system. (b) Describe how a digital signature is created. (c) Explain briefly what SSL (secure so

TCP / IP, Let me know the details of protocol tcp/ip

Let me know the details of protocol tcp/ip

What is meant by certificate revocation, QUESTION (a) Which PKI (Public...

QUESTION (a) Which PKI (Public Key Infrastructure) model is typically favored by business organization? (b) Give one possible use of the "extensions" field of an X.509 certi

Web accessibility initiative standards, Australian government sites were ma...

Australian government sites were mandated to conform to at least single 'A' level of the World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI) standards, by the end of

Tree decomposition, (a) Define what you understand by the following terms ...

(a) Define what you understand by the following terms in Network Flows: i) UnDirected Path ii) Directed Path iii) Directed Cycle. iv) Tree In each of the above, expla

Address resolution with table lookup, ADDRESS RESOLUTION WITH TABLE LOOKUP ...

ADDRESS RESOLUTION WITH TABLE LOOKUP : Resolution needs data structure that has information about address binding. A distinct address-binding table is used for every physical n

Introduction to network protocol, In this assignment, you are required to e...

In this assignment, you are required to emulate the operation of a link layer and network layer protocols in a small computer network. Your program should behave like a single node

Encryption key size-cryptography, Encryption Key Size When using ciphers...

Encryption Key Size When using ciphers, the size of crypto variable or key is quite important as the strength of many encryption applications and cryptosystems were measured by

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