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

Basic types of agent in order of increasing generality, Question 1: (a)...

Question 1: (a) Define Artificial Intelligence. (b) Briefly describe the categories for the definition of Artificial Intelligence. (c) Identify the four basic types of

Enterprise information security policy (eisp), Enterprise Information Secur...

Enterprise Information Security Policy (EISP) EISP also known as security policy directly supports the mission of the organization and sets the strategic direction, scope, and t

Explain the encryption model or symmetric cipher model, With explain the en...

With explain the encryption model the help of diagram. Symmetric cipher model uses the secret-key or a single-key for encryption/decryption purposes. It employs a symmetric encr

Routing tables and address masks, ROUTING TABLES AND ADDRESS MASKS Add...

ROUTING TABLES AND ADDRESS MASKS Additional information is saved in routing table. Destination is kept as network address. Next hop is saved as IP address of router. Address m

Selecting a risk control strategy-information security, Selecting a Risk Co...

Selecting a Risk Control Strategy Risk controls involve selecting one of the 4 risk control strategies for every vulnerability. The flowchart is shown in the figure given below

encrypt and decryption using rsa with the prime numbers, Problem (1) -...

Problem (1) - Alice, Bob and Charlie have a secret key a=3, b=4, c=5, respectively. - They want to find a common secret key using Diffie-Hellan key exchange protocol (with g

What are the ethical issues and implications, An injunction to 'think ethic...

An injunction to 'think ethically' about a situation is not helpful. Perhaps if one has a background in moral philosophy this would work, but usually both students and IT professio

Meaning of dns - domain name system, What do you understand by the DNS? Exp...

What do you understand by the DNS? Explain the usage of the resource rec or ds. Domain Name System is described below: The Domain Name Service (DNS) is the hierarchi

Explain symmetric and asymmetric encryption system, Question 1: (a) Dif...

Question 1: (a) Differentiate between symmetric and asymmetric encryption system. (b) Describe how a digital signature is created. (c) Explain briefly what SSL (secure so

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 "

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