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

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

What do you understand by demilitarized zone, Problem 1: What does the ...

Problem 1: What does the SNMP access policy show? SNMP community diagram SNMP access policy Problem 2: Does there exist any formal functional specificat

Explain the purpose of the dr and bdr, QUESTION a) Compare and contras...

QUESTION a) Compare and contrast between static and dynamic routing. b) What are the merits (five merits) and limitations (3 limitations) of using Open Shortest Path First

Linux, Discuss the risks of having a single root user

Discuss the risks of having a single root user

Explain how ethernet deals with collisions, (a) Describe how CSMA/CD operat...

(a) Describe how CSMA/CD operates and explain how Ethernet deals with collisions. (b) Describe how the subsequent protocols work: i. ARP ii. DHCP iii. DNS iv. SMTP (c) The

Cipher methods-cryptography, Cipher Methods There are 2 methods of encry...

Cipher Methods There are 2 methods of encrypting plaintext: • Bit stream method – every bit in the plaintext bit is transformed into a cipher bit one bit at a time. • Block cip

Http request message, Question (a) Consider that you enter the subsequent ...

Question (a) Consider that you enter the subsequent URL in the address bar of a popular web client and that both the server and client accepts HTTP version 1.1. i. What can be

The effect the incident has on your business, QUESTION There are gener...

QUESTION There are generally five factors that will influence how you respond to computer security incidents- The effect the incident has on your business Legal issue

Base lining-risk management, Base lining •    Organizations do not have ...

Base lining •    Organizations do not have any contact to each other •    No two organizations are identical to each other •    The best practices are a moving target •    K

Firewall analysis tools-information security, FIREWALL ANALYSIS TOOLS Th...

FIREWALL ANALYSIS TOOLS There are a number of tools automate remote discovery of firewall rules and assist the administrator in analyzing rules Administrators who feel wary of u

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