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

Legal, LEGAL, ETHICAL AND PROFESSIONAL ISSUES To minimize liabilities an...

LEGAL, ETHICAL AND PROFESSIONAL ISSUES To minimize liabilities and reduce risks, information security practitioner should: •    to understand current legal environment •    to s

Sending an arp message, Normal 0 false false false EN-U...

Normal 0 false false false EN-US X-NONE X-NONE

Distinguish between authorization and authentication, Question : (a) D...

Question : (a) Distinguish between authorization and authentication. (b) SSO (Single Sign On) implies a user logs in once and can access resources for a defined period of

Hardware, Hardware, Software, and Network Asset Identification What info...

Hardware, Software, and Network Asset Identification What information attributes to track is dependent on: •    Requires of organization/risk management efforts •    Management

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

Securities Issues in a company, 'Near Field Communication' (NFC) technologi...

'Near Field Communication' (NFC) technologies are expected to become commonplace in the near future. Some relevant features are these: A suitable device (such as a mobile pho

What are the intermediate systems and how they work, Question: a) Expla...

Question: a) Explain what the following intermediate systems are and how they work? i. Repeater ii. Bridge b) A service is formally specified by a set of primitives (op

Introduction to cryptography, INTRODUCTION TO CRYPTOGRAPHY Cryptography...

INTRODUCTION TO CRYPTOGRAPHY Cryptography The word cryptography is derived from Greek words kryptos, which means hidden and graphein, meaning to write, this is the process of

Explain the schemes for distribution of public keys, (a) What is a pseudora...

(a) What is a pseudorandom generator? Give an example describing how it works. (b) Explain the key components of a wireless network and their purpose. (c) Describe the authen

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