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

Differences between a hacker and a cracker, Question: (a) Which of the...

Question: (a) Which of the following is not a goal of security: i) detection ii) prevention iii) recovery iv) prosecution (b) You are an honest student. One day you

Types of idss and detection methods, Types of IDSs and Detection Methods ...

Types of IDSs and Detection Methods IDSs operate as network based, host based, or application based systems and focused on protecting network information assets. All the IDSs us

Routing protocol for a banking network, You have been asked to design a Ban...

You have been asked to design a Banking Network with two primary types of locations.  Branches that will have 3 subnets, one /25 subnet one /26 subnet for ABMS and one /26 s

Securing the network using a packet filter firewall, 1. Network Design ...

1. Network Design Design your network giving appropriate IP addresses for your hosts. Provide a topology and table showing your addressing scheme. 2. F i re wall po

Packet filtering firewall-dynamic packet filtering, Dynamic Packet Filterin...

Dynamic Packet Filtering Dynamic Packet Filtering is also referred to as stateful firewalling. Here the firewall maintains the status of connections as well. When a connection

Explain in des data encryption standard, Explain in DES Data Encryption Sta...

Explain in DES Data Encryption Standard : DES stands for Data Encryption Standard and is explained as follows: DES is at present the most widely used key cryptographic systems

Simplex data exchange, Simplex data exchange Simplex communication def...

Simplex data exchange Simplex communication defines to communication that happens in one direction only. Two definitions have made over time: a common definition, which is des

Explain belady''s anomaly, Belady's Anomaly Also known FIFO anomaly. G...

Belady's Anomaly Also known FIFO anomaly. Generally, on raising the number of frames given to a process' virtual storage, the program execution is faster, because lesser page

Lan topologies, Network can be distinguished by shape. According to which t...

Network can be distinguished by shape. According to which there are three most popular methodologies, which are shown as follows; Star Ring Bus

Hardware, Hardware, Software, and Network Asset Identification What info...

Hardware, Software, and Network Asset Identification What information attributes to track is dependent on: •    Requires of organization/risk management efforts •    Management

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