Placeholders for the plaintext characters, Computer Network Security

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).

Posted Date: 3/15/2013 5:53:48 AM | Location : United States

Related Discussions:- Placeholders for the plaintext characters, Assignment Help, Ask Question on Placeholders for the plaintext characters, Get Answer, Expert's Help, Placeholders for the plaintext characters Discussions

Write discussion on Placeholders for the plaintext characters
Your posts are moderated
Related Questions
RISK ASSESSMENT Risk assessment is a step in a risk management technique. Risk assessment is the determination of quantitative or qualitative value of risk related to a concrete

The first and foremost need of  any business is a role to perform for its client base, and for the spammer this will typically be the role of advertising products which, due to the

Example 3: Logic bombs In the year 2000, Timothy Lloyd was found responsible of causing $10 million and $12 million of damage to Omega Engineering, an American company specializ

Application-Based IDS Application-based IDS (AppIDS) is an advanced version of HIDS. It examines application for abnormal events. The ability to view encrypted data is the uniqu

(a) Briefly explain the following security goals provided by cryptography: confidentiality, authentication, integrity and non-repudiation. (b) State Kerckhoff's Princip

Question requires you to develop firewall rules based on a fictitious organisation. Scenario: You work for a security-conscious company, xC-Cure, who develop encryption tec

Probelm 1: Give the History and Evolution of Wireless Communication System. Complete explanation Probelm 2: Describe the process of Components Identification and cal

PACKET SNIFFERS A packet network protocol analyzer is a network tool which collects copies of packets from network and analyzes them. It can give network administrator with valu

INTRODUCTION TO RISK MANAGEMENT Risk management is the procedure of identifying and controlling risks facing an organization. Risk management is the discipline which is employed

How does the POP functions? What are the advantages/benefits of IMAP over POP? POP stands for Post Office Protocol, version 3 (POP3) is one of the easiest message access protoc