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

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

Cyber security, How to pretect my computer from attacking

How to pretect my computer from attacking

Tcp- reliable transport service, TCP-RELIABLE TRANSPORT SERVICE INTRO...

TCP-RELIABLE TRANSPORT SERVICE INTRODUCTION:  TCP is the major transport protocol architecture in the TCP/IP suite. It uses unreliable datagram function offered by IP whe

Limitations of firewall, Limitations of firewall Firewalls cannot prote...

Limitations of firewall Firewalls cannot protect a network if security rules are not followed properly by an organization or if the rules are not defined properly. Firewalls ar

Describe how the encapsulated security header protocol, Question: (a) ...

Question: (a) Give 2 benefits of using IPsec. (b) IPSec uses two protocol for security: Authentication Header protocol (AH) and the Encapsulated Security Header Protocol (

802.11 wireless lans and csma/ca, 802.11 WIRELESS LANs AND CSMA/CA:  ...

802.11 WIRELESS LANs AND CSMA/CA:  IEEE 802.11 is standard wireless LAN that needs radio signals at 2.4GHz. Its speed is 11Mbps. The older computers use radio signals at data

Elements of cryptosystems-cryptography, Elements of Cryptosystems Crypto...

Elements of Cryptosystems Cryptosystems is characteristically made up of algorithms, data handling techniques, and procedures which are combined in multiple ways to ensure confi

Threads and attacks-information security, THREADS AND ATTACKS Threat is ...

THREADS AND ATTACKS Threat is an object, person, or other entity which represents a constant danger to an asset. To make sound decisions about information security, management s

Design a network layout, QUESTION: (a) Below is a capture of an Ethern...

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 sourc

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