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

Wan architecture and wan service, MegaCorp INC. is a large manufacturing f...

MegaCorp INC. is a large manufacturing firm that operates 5 factories in Dallas, 4  factories in Los Angeles, and 5 factories in Albany, New York.  It operates a tightly  connected

Ring topology, RING topology all computers are connected in loop. A ring ...

RING topology all computers are connected in loop. A ring topology is a network topology in which every node connects to exactly two other devices, forming a single continuous pa

Network design approach, Problem a) Give three reasons why traditional ...

Problem a) Give three reasons why traditional Network Design approach is less appropriate for many of today's networks? b) The network requires of users are organized into m

Designing and coding of job search mechanism, Designing and coding of Job s...

Designing and coding of Job search mechanism: Project Title: FREEHIVE (Sep 2005- Nov 2006) Role             : Developer Domain         : Social Network Client

Describe the five-layer network using block diagrams, Problem 1: a) One...

Problem 1: a) One of the limitations of file processing systems is data inconsistency. Briefly explain with the help of an example what do you understand by this phrase. b)

Host-based ids, Host-Based IDS A host-based IDS (HIDS) resides on a part...

Host-Based IDS A host-based IDS (HIDS) resides on a particular computer or server and monitors activity only on that system. HIDS also called as system integrity verifiers as th

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

Limitations of firewall, Limitations of firewall Firewalls cannot prote...

Limitations of firewall Firewalls cannot protect a network if security rules are not followed properly by an organization or if the rules are not defined properly. Firewalls ar

Short term scheduler, Short term Scheduler function , also shown as a disp...

Short term Scheduler function , also shown as a dispatcher runs most frequently, and creates the finest-grained decision of which program could run next. This scheduler is called

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

Question: (a) Draw the waveform for an asynchronous transmission with the following specifications: Character "H", one even parity bit, one start bit, one stop bit, and a b

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