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

Protocols for secure communications-cryptography, Protocols for Secure Comm...

Protocols for Secure Communications Securing Internet Communication by using S-HTTP and SSL Secure Socket Layer (SSL) protocol is a protocol that uses public key encryption t

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

What is information-information security, What is information Informatio...

What is information Information comprises the meanings and interpretations which people place upon the facts, or data. The value of information springs from the ways it can be i

Explain how the framework will align to the model, MB Enterprise Systems Lt...

MB Enterprise Systems Ltd based in Mauritius is a company specialized in application development with Europe as the main customer base. The company has implemented CMMI and has rec

What is triple key management scheme, Q. What is Triple Key Management Sche...

Q. What is Triple Key Management Scheme? The triple key management mechanism provides optimum security by enabling the use of two pre-deployed keys for each of the WS nodes, an

Selecting a risk control strategy, Selecting a Risk Control Strategy Risk...

Selecting a Risk Control Strategy Risk controls involve selecting one of the 4 risk control strategies for every vulnerability. The flowchart is shown in the figure given below

Security and basics steps in writing thesis, how can i start thesis? Please...

how can i start thesis? Please mention so of examples?

Introduction to network protocol, In this assignment, you are required to e...

In this assignment, you are required to emulate the operation of a link layer and network layer protocols in a small computer network. Your program should behave like a single node

Man-in-the-middle attacker, - Alice, Bob and Charlie have a secret key a=3,...

- Alice, Bob and Charlie have a secret key a=3, b=4, c=5, in that order. - They would like to find a common secret key using Diffie-Hellan key exchange protocol (with g=2, p=5).

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