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

Quote, How much would it cost to have a project completed by tomorrow night...

How much would it cost to have a project completed by tomorrow night?

Computer forensic, discuss the merits and demerits of computers freezing

discuss the merits and demerits of computers freezing

Describe how ethernet deals with collisions, Problem (a) The IEEE 802 seri...

Problem (a) The IEEE 802 series of standards describe both the Physical and Data Link layers of their respective technologies. Two important standards are 802.3 and 802.5, respect

Packet filtering firewall, Packet Filtering Firewall Packet filtering i...

Packet Filtering Firewall Packet filtering is a network security mechanism that works by controlling what data can flow in and out of the network. The basic device that interco

Packet filtering firewall-dynamic packet filtering, Dynamic Packet Filterin...

Dynamic Packet Filtering Dynamic Packet Filtering is also referred to as stateful firewalling. Here the firewall maintains the status of connections as well. When a connection

CS, Discuss how developers should apply the following countermeasures to im...

Discuss how developers should apply the following countermeasures to improve the security of their code:

What type of rfid tag is more appropriate for ws-pass, Consider the followi...

Consider the following case study: In order to avoid criticisms of their existing manned road-toll payment system on its private road, WS-Pass has decided to adopt an automated

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,

Example of a public key algorithm, Question : (a) There are two approa...

Question : (a) There are two approaches for providing confidentiality for packets in a network using symmetric encryption: End-to-End Encryption and Link Encryption. State wh

Programming, SDES encryption and decryption

SDES encryption and decryption

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