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

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

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

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

Ring topology, RING TOPOLOGY In this topology of network the devices a...

RING TOPOLOGY In this topology of network the devices are connected to each other in packed loop. In this network first computer passes data packet to the second and then seco

Virtual packets, VIRTUAL PACKETS These data packets serve same reason ...

VIRTUAL PACKETS These data packets serve same reason in Internet as frames on LAN. Every packet has a header. Routers, which are normally gateways, transfer packets between ph

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

Direct sequence modulation, Question 1 a) Provide three advantages of ...

Question 1 a) Provide three advantages of using optical fiber. b) Distinguish between "Direct Sequence Modulation" and "Frequency Hopping" c) Decribe the purpose of using "

Computer Security, I have an assignment of Computer Security to submit. Wil...

I have an assignment of Computer Security to submit. Will you guys help me making my assignment???

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

A small isp requests your help, QUESTION A small ISP requests your help...

QUESTION A small ISP requests your help. The technicians report that they have had no downstream access to the Internet. They believe the problem lies with their access provide

Explain the main stages in the penetration testing process, Question: (...

Question: (a) i. Explain what is meant by Discretionary Access Control and Mandatory Access Control ii. Which method would be the most effective to ensure that users do

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