Find the possible deciphering transformations, Computer Network Security

Assignment Help:

Question:

(a) A string of ciphertext was enciphered using an a±ne transformation of single letters in a 28-letter alphabet consisting of A to Z, a blank and a?, where A to Z have numerical equivalents 0 to 25, blank=26, ?=27. A frequency analysis reveals that the the first, second and third most common letters of this ciphertext are B, ? and I, respectively. Suppose that the first and second most common letters in an English language text written in this 28-letter alphabet are ` '(blank) and E, respectively.

(i) Find the possible deciphering transformations.

(ii) Using the fact that T, is the third most common letter in the English language (of our 28 letters), find the right deciphering transformation.

(b) The ciphertext

¡GSTMTSI XJMUIGHRFKYMV

was generated using a 2£2 enciphering matrix with a 29¡letter alphabet, where A to Z have numerical equivalents 0 to 25, blank=26, !=27, and ¡ = 28. Given that the last five letters of the plaintext are A¡ONE, determine the complete plaintext.


Related Discussions:- Find the possible deciphering transformations

Explain transposition ciphers and substitution cipher, What do you understa...

What do you understand by cryptanalysis? Discuss about the transposition ciphers substitution cipher, and onetime pads. The messages which are intended to transmit secretly and

Benchmarking-information security, Benchmarking An alternative approach to...

Benchmarking An alternative approach to risk management is Benchmarking. It is process of seeking out and studying practices in other organizations which one’s own organization de

Limitations of firewall, Limitations of firewall Firewalls cannot prote...

Limitations of firewall Firewalls cannot protect a network if security rules are not followed properly by an organization or if the rules are not defined properly. Firewalls ar

Securing the components-information security, SECURING THE COMPONENTS Co...

SECURING THE COMPONENTS Computer can be subject of an attack or the object of an attack. When subject of an attack, computer is used as lively tool to conduct attack. The figure

Marketing, what are the participant of marketing channal?

what are the participant of marketing channal?

Define half-duplex, A  half-duplex (HDX) system gives communication in b...

A  half-duplex (HDX) system gives communication in both directions, but only one direction at a time. Hardly, once a party stats receiving a signal, it must need for the transmi

Network intrusion system, In this work a network intrusion system (package)...

In this work a network intrusion system (package) must implement based on high interaction honeypots. There are two honeypots with different platforms (ubuntu and windows server 20

Describe what the term session hijacking means, An overall rise in mobility...

An overall rise in mobility, coupled with the falling cost of Wi-Fi equipment, has led to a proliferation of Wi-Fi hot spots in public areas to provide Internet accessibility. Thus

Evaluations, Evaluations, Assessment, and Maintenance of Risk Controls W...

Evaluations, Assessment, and Maintenance of Risk Controls When the control strategy has been implemented, it should be monitored and measured on an ongoing basis to determine ef

Architecture of www named world wide web, Write down short notes on the arc...

Write down short notes on the architecture of WWW which is World Wide Web. WWW which means The World Wide web or the web is a repository of information spread worldwide and rel

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