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

Cyber security, How to pretect my computer from attacking

How to pretect my computer from attacking

Application-based ids, Application-Based IDS Application-based IDS (AppI...

Application-Based IDS Application-based IDS (AppIDS) is an advanced version of HIDS. It examines application for abnormal events. The ability to view encrypted data is the uniqu

Transmision imparment, What are Transmission Impairments? Explain the follo...

What are Transmission Impairments? Explain the following concepts with respect to Transmission Impairments a) Attenuation b) Delay Distortion c) Noise ion #Minimum 100 words ac

Threat identification-risk management, Threat Identification After ident...

Threat Identification After identifying and performing a primary classification of an organization’s information assets, the analysis phase moves onto an examination of threats

Ip datagrams, on LAN,where are IP datagrams transported?

on LAN,where are IP datagrams transported?

Imap and pop functions, How does the POP functions? What are the advantages...

How does the POP functions? What are the advantages/benefits of IMAP over POP? POP stands for Post Office Protocol, version 3 (POP3) is one of the easiest message access protoc

Risk management discussion points, Risk Management Discussion Points Org...

Risk Management Discussion Points Organizations should define level of risk it can live with Risk appetite: it defines quantity and nature of risk which organizations are wil

Ids-information security, IDS Intrusion is a attack on information assets...

IDS Intrusion is a attack on information assets in which instigator attempts to gain entry into or disrupt normal system with harmful intent Incident response is an identificatio

Half-duplex and full-duplex mode of transmission, Question: a. State br...

Question: a. State briefly three reasons why computer networks are used? b. Differentiate between simplex, half-duplex and full-duplex mode of transmission. c. State any

Ids response behavior, IDS RESPONSE BEHAVIOR Once IDS detects an anomalo...

IDS RESPONSE BEHAVIOR Once IDS detects an anomalous network situation, it has a number of options. IDS responses to external stimulation can be classified as active or passive.

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