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

What do you meant by the term diffusion and confusion, Question: (a) W...

Question: (a) What do you meant by the term diffusion and confusion? Explain how diffusion and confusion can be implemented. (b) Distinguish between authorisation and auth

What is the benefit of adopting a password aging policy, QUESTION (a) H...

QUESTION (a) Hashing and salting is commonly used as password storage techniques for most applications. Describe how hashing and salting enable secure storage of password (b

Udp interaction, UDP INTERACTION  UDP follows four kinds of interactio...

UDP INTERACTION  UDP follows four kinds of interaction 1-to-1: One application can interact with one application. 1-to-many: One application can interact with many

Explain the concept behind digital signature, Question: a) Differenti...

Question: a) Differentiate between ‘Gross Settlement' and ‘Multilateral Net Settlement' providing suitable examples where necessary to support your answer. b) Differentia

How to create a security policy, Five years ago, Calgary Kids' Cloth Ltd wa...

Five years ago, Calgary Kids' Cloth Ltd was just a small retail store in downtown Calgary. The company started their own factory in SE Calgary to produce outdoor clothes for kids.

The major decision hierarchy for disclosing security problem, QUESTION ...

QUESTION The major decision hierarchy for disclosing security problems is if the problem is with the product owned by the business or if it is used by the business. Although th

Different architectures for wireless networks, (a) What are the different a...

(a) What are the different architectures for wireless networks? (b) Explain how WEP authentication and encryption works, describe the vulnerability. (c) In what ways are secu

Packet filtering firewall-stateless packet filtering, Stateless Packet Filt...

Stateless Packet Filtering Stateless or static packet filtering is the most straightforward kind of packet filtering that allows or disallows data transfer based on the addres

Data classification and management, Data Classification and Management C...

Data Classification and Management Corporate and military organizations use a several of classification schemes. Information owners are responsible for classifying information a

Asset identification and valuation-information security, ASSET IDENTIFICATI...

ASSET IDENTIFICATION AND VALUATION This process begins with identification of assets that includes all elements of an organization’s system (people, procedures, data and informa

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