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

Wireless networks, Wireless Networks The origin of wireless networks a...

Wireless Networks The origin of wireless networks and their ubiquity in the technological environment poses a new type of exposure and vulnerability for network security. Cont

Describe benefits of effective communication, Question: (a) Explain the...

Question: (a) Explain the following terms: Information Communication Technology, Operating System and Application Software. (b) Define what a computer is, give four anatomi

Softbank theft of consumer data -information security, Example : Softbank –...

Example : Softbank – theft of consumer data for extortion Softbank of Japan offers broadband Internet services across Japan through 2 subsidiaries – Yahoo! BB and Softbank BB. I

Syntax conversion, Write down the significance of the syntax conversion . S...

Write down the significance of the syntax conversion . Syntax Conversion is described below: Syntax conversion is a significant function carried out in the presentation layer. I

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:

Explain the close procurement project process, Question 1: Why do we ne...

Question 1: Why do we need a Law of Contract? a Explanation Reasons to have a law of contract b Explain the close procurement project process - Explanation (causes,

Access controls-information security, Access Controls Access controls ad...

Access Controls Access controls addresses admission of a user into a trusted area of organization. It comprises of a combination of policies & technologies. The ways to control

Categories of controls-risk management, Categories of Controls Controlli...

Categories of Controls Controlling risk through mitigation, avoidance or transference is accomplished by implementing controls. There are 4 effective approaches to select the co

Ciphertext, Encode the following plaintext, using the Caesar cipher: ...

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

Trap and trace systems-information security, TRAP AND TRACE SYSTEMS Trap...

TRAP AND TRACE SYSTEMS Trap and Trace Systems use techniques to detect an intrusion and trace it back to its source. Trap comprises of honey pot or padded cell and alarm. The dr

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