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

Explain the operation of the matchmaker middle agent, Question 1: (a) E...

Question 1: (a) Explain the operation of the "matchmaker" middle agent. (b) Describe why broker middle agents are more efficient in terms of the time taken for a service to

What is the role of an intrusion detection system, Problem: (a) What i...

Problem: (a) What is a firewall and which are its most important tasks? (b) What is the difference between default deny and default permit? Which advantages and disadvanta

CRC, CRC in matlab

CRC in matlab

Describe the use of control channels in gsm network, Problem 1: What is...

Problem 1: What is the function of AUC in the GSM architecture? Explanation of HLR(AUC) Architecture of GSM Problem 2: Show the layered architecture of t

Secure a wireless network, Secure a Wireless Network WIRELES Most onli...

Secure a Wireless Network WIRELES Most online retailers provide some type of privacy statement. Many statements are long, and appear in small print, and many appear to be simi

Cryptographic algorithms-cryptography, Cryptographic algorithms Cryptogr...

Cryptographic algorithms Cryptographic algorithms are broadly classified into two broad categories. They are stated below 1.  Symmetric Encryption and 2.  Asymmetric Encryptio

Address resolution , Mapping between a hardware address and a protocol addr...

Mapping between a hardware address and a protocol address is known Address Resolution. A router or host uses address resolution when it requires to transmit a packet to another dev

Ids response behavior, IDS RESPONSE BEHAVIOR Once IDS detects an anomalo...

IDS RESPONSE BEHAVIOR Once IDS detects an anomalous network situation, it has a number of options. IDS responses to external stimulation can be classified as active or passive.

Calculate alpha and beta value caesar cipher, Task 1 a. Consider the t...

Task 1 a. Consider the table showing the relative frequencies of letters in English. Arrange the frequencies from largest to smallest, and make a cumulative plot, using Exc

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

on LAN,where are IP datagrams transported?

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