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

Enterprise information security policy (eisp), Enterprise Information Secur...

Enterprise Information Security Policy (EISP) EISP also known as security policy directly supports the mission of the organization and sets the strategic direction, scope, and t

Sequential label and supply, What questions should Iris ask Charlie about t...

What questions should Iris ask Charlie about the new job, about Kelvin''s team, and about the future of the company?

Explain briefly the role of the physical layer, a) Calculate the CRC for th...

a) Calculate the CRC for the frame below: Frame: 1101011011 Generator: 10011 Message after appending 4 zero bits: 11010110110000 b) OSI refers to a system in which any

Ip datagrams, on LAN,where are IP datagrams transported?

on LAN,where are IP datagrams transported?

How does message switching operate, Question: Human telephone conversat...

Question: Human telephone conversations are characterized by irregular pauses, alternating with irregular bursts of speech. In contrast, communication via computers is char

Information classification, INFORMATION CLASSIFICATION The classificatio...

INFORMATION CLASSIFICATION The classification of information is an important aspect of policy and a control for the information protection. A clean desk policy stipulates that a

Compare the suitability and properties of isdn and adsl, Question : An a...

Question : An aircraft manufacturing company is considering linking the network of one of its offices to the network of its Headquarter using either xDSL or ISDN. i. Compare

Transport protocols, TRANSPORT PROTOCOLS: Give application-to-appl...

TRANSPORT PROTOCOLS: Give application-to-application communication. Require extended addressing mechanisms to check applications. Are known end-to-end communicatio

Unguided media, Unguided Media This is the wireless media that transfe...

Unguided Media This is the wireless media that transfer electromagnetic waves without using a physical media. Waves are broadcast through the air. This is performing through r

The cost benefit analysis (cba) formula, The Cost Benefit Analysis (CBA) Fo...

The Cost Benefit Analysis (CBA) Formula CBA determines that whether the control alternative being evaluated is worth cost incurred to control vulnerability or not. CBA easily ca

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