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

Major difference between a virus and a worm, Question: (a) State wheth...

Question: (a) State whether the following statements are TRUE or FALSE. Justify your answer. i. A good site security policy will require that users use computer generated p

What is an autonomous system, QUESTION 1: a) Differentiate between a r...

QUESTION 1: a) Differentiate between a routing protocol and a routed protocol. b) Describe any three design goals of Routing protocols. c) Lists some of the features shared

Bus topology, BUS TOPOLOGY In a bus topology all devices are attached ...

BUS TOPOLOGY In a bus topology all devices are attached to a single long cable and any device can send data to any other device. For this function, coordination is needed to d

Cyber security, How to pretect my computer from attacking

How to pretect my computer from attacking

Research paper, how much would you charge for minimum 20 pages

how much would you charge for minimum 20 pages

Explain the security service - confidentiality, Question: (a) Explain t...

Question: (a) Explain the following security services: Confidentiality, Availability. (b) Which attack will be used to bypass even the best physical and logical security m

Routers, Routers They transfer packets among multiple interconnected n...

Routers They transfer packets among multiple interconnected network machines (i.e. LANs of different kind). They perform in the data link, physical and network layers. They ha

Explain the rsa algorithm, Question: (a) What is the minimum length of...

Question: (a) What is the minimum length of a password that could be considered to be "strong" in the context of today's computing power? (b) The security of a PIN system,

Categories of controls-risk management, Categories of Controls Controlli...

Categories of Controls Controlling risk through mitigation, avoidance or transference is accomplished by implementing controls. There are 4 effective approaches to select the co

Explain the encryption model or symmetric cipher model, With explain the en...

With explain the encryption model the help of diagram. Symmetric cipher model uses the secret-key or a single-key for encryption/decryption purposes. It employs a symmetric encr

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