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

Udp interaction, UDP INTERACTION  UDP follows four kinds of interactio...

UDP INTERACTION  UDP follows four kinds of interaction 1-to-1: One application can interact with one application. 1-to-many: One application can interact with many

Problem of spam mail, Topic -Spam is an ever-growing problem, with some net...

Topic -Spam is an ever-growing problem, with some network administrators reporting that 90% or moreof the email delivered to their mail servers is spam. Identify and briefly evalua

Object tracking using wireless sensor networks, This project involves the d...

This project involves the design and development of a simulation environment of many sensors tagging material/ machinery/equipment/etc in a warehouse site to help monitor and manag

Nessus vulnerability, You see two IP addresses. The IP address 192.168.58.1...

You see two IP addresses. The IP address 192.168.58.130 is the one of Bt4. The IP address 192.168.58.133 has ports 135 and 445 open; which indicates that it is a Windows machine. S

Characteristics of radial basis function neural networks, Problem : (a)...

Problem : (a) Provide one possible classification of PCA, ART, RBF, and Fuzzy ARTMAP networks. (b) Describe in detail the characteristics of Radial Basis Function Neural Net

Describe phishing attacks, QUESTION (a) (i) Describe Phishing attacks. ...

QUESTION (a) (i) Describe Phishing attacks. (ii) Distinguish between Phishing and Spear Phishing attacks. (b) Describe two instances where an attacker sniffing on a netwo

Udp communication semantics, UDP COMMUNICATION SEMANTICS:  UDP needs I...

UDP COMMUNICATION SEMANTICS:  UDP needs IP for all delivery, that is, similar best effort delivery as IP. To use UDP, an application have to either be immune to the causes or

Explain rsa encryption, (a) Describe RSA encryption. (b) For an RSA encr...

(a) Describe RSA encryption. (b) For an RSA encryption the values of the primes are: p=29, q=31. select e=11, evaluate the public and private keys. (c) How can RSA be used fo

Example of an attack against a windows, The objective of this example is to...

The objective of this example is to demonstrate the steps required for a successful attack against a vulnerable Windows XP SP2 system. It will show: a) how Nessus can be used to di

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

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