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

Mitigate risks in an information security management system, Question: ...

Question: (a) What are the various options to mitigate risks in an Information Security Management System (ISMS)? For each option specify an instance where it can be used.

Star topology, In Star topology all computers are connected using a cen...

In Star topology all computers are connected using a central device known as hub. Star networks are one of the most general computer network topologies. In its simplest way, a

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.

Mastering the complexity of network system, To master the complexity one mu...

To master the complexity one must apply the given points. CONCENTRATE IN UNDERSTANDING THE CONCEPTS: Instead of details of wires used to connect computers to a specif

Linux, Discuss the risks of having a single root user

Discuss the risks of having a single root user

Computer security, Implementing an effective online authentication scheme i...

Implementing an effective online authentication scheme in practice faces many challenges. Systems with highly sensitive data often require multifactor authentication. But, requirin

Provide a labelled drawing of a standard serial port, Question 1: (a) W...

Question 1: (a) With the help of a diagram show the basic structure of a computer system. (b) Explain as fully as you can each of the parts mentioned above. (c) What are

Technology, how can you enter the ASVAB practice test on line?

how can you enter the ASVAB practice test on line?

What do you meant by network address translation, Problem: (a) What do ...

Problem: (a) What do you meant by Network Address Translation (NAT)? Why is it used? (b) Given the following information by your ISP about your newly acquired Frame Relay c

Describe the procedure known as byte stuffing, Question: (a) For the b...

Question: (a) For the bit stream 010011, sketch the waveforms for each of the code indicated. Assume the following: the signal level for the previous bit for NRZI was a 1

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