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

Explain how ftp works, QUESTION (a) FTP is a protocol used for the de...

QUESTION (a) FTP is a protocol used for the delivery of files across networks. Explain how FTP works (support your answer with a diagram). (b) How does TCP perform the gi

Explain any two types of security policies, Question 1 Explain any two typ...

Question 1 Explain any two types of security policies Question 2 What is security attack? Explain with examples Question 3 Explain different characteristics that i

Introduction to risk management and its component, INTRODUCTION TO RISK MAN...

INTRODUCTION TO RISK MANAGEMENT Risk management is the procedure of identifying and controlling risks facing an organization. Risk management is the discipline which is employed

Packet filtering firewall-stateless packet filtering, Stateless Packet Filt...

Stateless Packet Filtering Stateless or static packet filtering is the most straightforward kind of packet filtering that allows or disallows data transfer based on the addres

Secure routing protocols for wireless sensor networks, Q. Secure routing Pr...

Q. Secure routing Protocols for Wireless Sensor Networks? A secure routing information protocol enables effective implementation of authentication and integrity checking defens

Draw the network layout, Question : a) Below is a capture of an Etherne...

Question : a) Below is a capture of an Ethernet II frame which contains an IPv4 packet and a TCP segment. Give the source MAC address for the frame in hexadecimal; the source I

Explain in des data encryption standard, Explain in DES Data Encryption Sta...

Explain in DES Data Encryption Standard : DES stands for Data Encryption Standard and is explained as follows: DES is at present the most widely used key cryptographic systems

Calculate euler totient function value, (a) Explain the importance of the ...

(a) Explain the importance of the Euler Totient function in Cryptography. Calculate Euler Totient function value, φ(1280). (b) Explain the role of the Authentication Server (

List vulnerabilities of using wep, Question: The Wired Equivalent Priv...

Question: The Wired Equivalent Privacy (WEP) standard was created in order to give wireless networks safety and security features similar to that of wired networks. (a) L

Internet protocol(ip), Internet Protocol IP Gives computer-to-comp...

Internet Protocol IP Gives computer-to-computer communication. Host and receiver addresses are computers. This is also known machine-to-machine communication.

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