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

Estimate the average throughput, Question (a) Estimate the average thr...

Question (a) Estimate the average throughput between two hosts given that the RTT for a 100 bytes ICMP request-reply is 1 millisecond and that for a 1500 bytes is 2 millisecon

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

Cryptographic algorithms-cryptography, Cryptographic algorithms Cryptogr...

Cryptographic algorithms Cryptographic algorithms are broadly classified into two broad categories. They are stated below 1.  Symmetric Encryption and 2.  Asymmetric Encryptio

Use the chinese remainder theorem to evaluate x, Use the Chinese remainder ...

Use the Chinese remainder theorem to evaluate x from the following simultaneous congruences: x ≡ 1 (mod 2); x ≡ 2 (mod 3); x ≡ 3 (mod 5). Calculate gcd(14526, 2568). (

Assignment, for making the assignment

for making the assignment

Future threats to network security and planning for those th, I need a help...

I need a help on how to write good assignment on the above topic

Vulnerability scanners, VULNERABILITY SCANNERS Active vulnerability scan...

VULNERABILITY SCANNERS Active vulnerability scanners scan networks for detailed information, it initiate traffic to determine security holes. This scanner identifies usernames a

Algorithm, algorithm on simple intrest

algorithm on simple intrest

Explain the various costs of quality, Problem 1: Show what are the bene...

Problem 1: Show what are the benefits of project quality management? • Customer satisfaction • Reduced cost • Increased competitiveness • Fulfilment of social and economic r

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