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

Audit or review of the information security issues, Using the selected appr...

Using the selected approach, you should then conduct an audit or review of the information security issues associated with the use of computing facility and report on the findings.

Structure of a typical frame relay, Problem a) Consider a 1000 Mbps Eth...

Problem a) Consider a 1000 Mbps Ethernet with a single Store-N-Forward switch mid-way in the path between two nodes A and B. Assume that there are no other nodes on the network

What is triple key management scheme, Q. What is Triple Key Management Sche...

Q. What is Triple Key Management Scheme? The triple key management mechanism provides optimum security by enabling the use of two pre-deployed keys for each of the WS nodes, an

Using Technology as Experience Framework, Write a two to three (2-3) page p...

Write a two to three (2-3) page paper in which you: Explain how the Web user interfaces help donors to make decisions. Relate the emotional thread demonstrated in the case study to

What is the maximum achievable data rate, Question: a) How many bits pe...

Question: a) How many bits per second can be sent on a noiseless 4 MHz channel if four-level digital signals are used? b) If a binary signal is sent over a 3 KHz channel who

Routers, Routers They transfer packets among multiple interconnected n...

Routers They transfer packets among multiple interconnected network machines (i.e. LANs of different kind). They perform in the data link, physical and network layers. They ha

Define byte stuffing, Sometimes the special character may see in data and a...

Sometimes the special character may see in data and as a part of data they will be misinterpreted as packet data. The solution to this cause is Byte stuffing.   In general to

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

Describe the process of components identification, Probelm 1: Give the ...

Probelm 1: Give the History and Evolution of Wireless Communication System. Complete explanation Probelm 2: Describe the process of Components Identification and cal

Limitations of firewall, Limitations of firewall Firewalls cannot prote...

Limitations of firewall Firewalls cannot protect a network if security rules are not followed properly by an organization or if the rules are not defined properly. Firewalls ar

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