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

Describe the time limit problem, Problem: (a) Use a simple example to ...

Problem: (a) Use a simple example to explain what is meant by a finite state machine. (b) Describe the time limit problem in an interrupt-driven system. (c) A certain m

Intercultural sensitivity: recognising differences, Intercultural sensitivi...

Intercultural sensitivity: recognising differences You represent a Mauritian computer company which is negotiating to buy hardware from a manufacturer in Japan. In your first

Computer fundamentals, Ask You have been asked by a new client to assist i...

Ask You have been asked by a new client to assist in setting up a new computer for her coffee shop. She has just purchased the newest Apple computer from an online site. Should wou

Write pseudocode for the password guessing algorithm, Write Pseudocode for ...

Write Pseudocode for the password guessing algorithm: Consider the following authentication protocol: Client Transmission Host

Fuckkkkk, Ask question #Minimum.. 100 words accepted#

Ask question #Minimum.. 100 words accepted#

Public key cryptosystem based on rsa technology, Problem: (a) What is ...

Problem: (a) What is the minimum length of a password that could be considered to be "strong" in the context of today's computing power? (b) The security of a PIN system,

It service support within the itil framework, Problem (a) IT Service Suppo...

Problem (a) IT Service Support within the ITIL framework is divided in a number of processes. Compare and contrast the following processes: i. Incident Management and Problem M

CS, Discuss how developers should apply the following countermeasures to im...

Discuss how developers should apply the following countermeasures to improve the security of their code:

Routing protocol for a banking network, You have been asked to design a Ban...

You have been asked to design a Banking Network with two primary types of locations.  Branches that will have 3 subnets, one /25 subnet one /26 subnet for ABMS and one /26 s

Risk control strategies-, Risk Control Strategies Once the ranked vulner...

Risk Control Strategies Once the ranked vulnerability risk worksheet has created, they should choose one of following 4 strategies to control each risk: •Apply safeguards which

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