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

Access control matrix, You are provided with 3000 sample keystrokes for 5 u...

You are provided with 3000 sample keystrokes for 5 users mentioned above. You can find this data using the ‘Lab 2 User Data' link in the ‘Lab 2' folder on Blackboard. Please note t

What is network address translation, Question: (a) What is Network Add...

Question: (a) What is Network Address Translation (NAT)? Why is it used? (b) Given a following information by your ISP about your newly acquired Frame Relay connection:

Discuss the influence the commercial operations, Question: A regional p...

Question: A regional police force has the following corporate objectives: ? to reduce crime and disorder; ? to promote community safety; ? to contribute to delivering just

What is feedforward multilayer perceptron neural network, Question: (a)...

Question: (a) Explain and illustrate with a drawing the three-layer feedforward multilayer perceptron neural network. (b) Summarize the standard backpropagation algorithm in

Securing the network using a packet filter firewall, 1. Network Design ...

1. Network Design Design your network giving appropriate IP addresses for your hosts. Provide a topology and table showing your addressing scheme. 2. F i re wall po

What is a firewall, QUESTION (a) Define and distinguish between Electro...

QUESTION (a) Define and distinguish between Electronic Commerce and Electronic Business (b) According to you what are the benefits that Electronic Commerce can brings to org

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

Cyclic redundancy check (crc), CYCLIC REDUNDANCY CHECK (CRC) To activa...

CYCLIC REDUNDANCY CHECK (CRC) To activate a network system to check move error without increasing the amount of information in every packet another most successful method is m

Draw the network layout, Question : a) Below is a capture of an Etherne...

Question : a) Below is a capture of an Ethernet II frame which contains an IPv4 packet and a TCP segment. Give the source MAC address for the frame in hexadecimal; the source I

The Security Systems Development Life Cycle (SecSDLCtle.., #Under what circ...

#Under what circumstances would the use of a SecSDLC be more appropriate than an SDLC?

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