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

CS, Discuss how developers should apply the following countermeasures to im...

Discuss how developers should apply the following countermeasures to improve the security of their code:

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

Network security attacks, (a) Show four Network Security attacks. How do th...

(a) Show four Network Security attacks. How do they compromise security? (b) In what ways do the following devices or services contribute to security: (i) Firewall (ii) In

Extended euclidean algorithm, (a) Using the extended Euclidean algorithm, ...

(a) Using the extended Euclidean algorithm, find the multiplicative inverse of 504 mod 67. (b) Decrypt the following ciphertext, which has been encrypted using Caesar cipher:

Address masks, ADDRESS MASKS To identify receiver, network apply addre...

ADDRESS MASKS To identify receiver, network apply address mask to receiver address and calculate to network address in routing table. It can use Boolean 'and' to calculate the

Explain the close procurement project process, Question 1: Why do we ne...

Question 1: Why do we need a Law of Contract? a Explanation Reasons to have a law of contract b Explain the close procurement project process - Explanation (causes,

TCP / IP, Let me know the details of protocol tcp/ip

Let me know the details of protocol tcp/ip

Develop a preliminary simulation model, Question: (a) State the strong ...

Question: (a) State the strong law of large numbers. (b) Data have been collected on response times (in minutes) at a fire station. The data are 2:7 1:8 0:8 1:4 1:2 (i

Media, what is guided media or unguided media

what is guided media or unguided media

Digital certificates, A Certificate presents an organization in an official...

A Certificate presents an organization in an official digital form. This is same to an electronic identity card which serves the purpose of Identifying the owner of the certificate

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