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

Information and network security, Information and Network Security Part ...

Information and Network Security Part 1- Recovery of an encrypted `word' using a forward search attack. Complete and correct summary for part 1. Adequately commented, clea

Derive the transmitted crc header checksum, QUESTION (a) Consider the f...

QUESTION (a) Consider the following digital bit stream 01001100 is to be encoded in: i. NRZ-I ii. Pseudoternary iii. Manchester iv. Differential Manchester Show th

#title.TIPS., 1. For this project, assume that an organization has five ser...

1. For this project, assume that an organization has five servers. Server 1 has a TCO of $25,000, Servers 2 and 3 have a TCO of $37,000 each, and the remaining two servers— Servers

What is the maximum achievable data rate, Question: a) How many bits pe...

Question: a) How many bits per second can be sent on a noiseless 4 MHz channel if four-level digital signals are used? b) If a binary signal is sent over a 3 KHz channel who

Calculate the dynamic range of the 16-bit scanner, You are hired as a consu...

You are hired as a consultant to help design a digital library in which books are scanned and stored digitally and made available to users of the World Wide Web. Assume that the li

Develop a tcp-based client-server socket program, Develop a TCP-based clien...

Develop a TCP-based client-server socket program for transferring a large message. The message transmitted from the client to server is read from a large file (size is about 30000

Software vulnerabilities, 1.  We used the National Vulnerability Database. ...

1.  We used the National Vulnerability Database. Select a recent vulnerability from that Database and analyse it from the following aspects: Criticality level Impact in

Access control matrix, You are provided with 3000 sample keystrokes for 5 u...

You are provided with 3000 sample keystrokes for 5 users mentioned above. You can find this data using the ‘Lab 2 User Data' link in the ‘Lab 2' folder on Blackboard. Please note t

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