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

Functional areas in network management, Question 1 a) Explain how CSMA...

Question 1 a) Explain how CSMA/CD works. b) Describe the term "exponential back-off". c) Describe the differences between "circuit switching" and "packet switching". d) Th

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

Components of an information system, COMPONENTS OF AN INFORMATION SYSTEM ...

COMPONENTS OF AN INFORMATION SYSTEM The components of an information system are software, data, hardware, people, procedures and Networks. These 6 components are critical to ena

ISDN, Explain the architecture of ISDN.....?

Explain the architecture of ISDN.....?

Spambot detection - spam mail, Spambot Detection: The  previous studie...

Spambot Detection: The  previous studies in this field  have focused on content and meta-content based features.  The main assumption in this area of spam detection of late is

The security systems development life cycle (secsdlc), The Security Systems...

The Security Systems Development Life Cycle (SecSDLC) The same phases which is used in traditional SDLC can be adapted to support specialized implementation of IS project,At its

Evaluate the sample correlation between y and z, Question: (a) Data on ...

Question: (a) Data on four variables are stored in a file called file1.dat. The first line of the file is the variable names f, x, y and z. Give the R commands to (i) read t

Explain belady''s anomaly, Belady's Anomaly Also known FIFO anomaly. G...

Belady's Anomaly Also known FIFO anomaly. Generally, on raising the number of frames given to a process' virtual storage, the program execution is faster, because lesser page

Bus topology, In BUS topology every computer is directly connected to p...

In BUS topology every computer is directly connected to primary network cable in a single way. Bus networks are the easiest way to connect multiple users, but can have problems

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