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

Network security, Network security has become much more complex than ever b...

Network security has become much more complex than ever before. New types and sources of network security threats, always-on high-speed Internet connections, wireless networking, a

Network analysis and network representation of a project, Question: Net...

Question: Network diagrams combine with a set of systematic analysis procedures, serve to remedy the shortcomings of the Gantt chart. Explain the following terms used in the ne

Calculate the total latency, Question (a) Inspect the following ifconfi...

Question (a) Inspect the following ifconfig output of an IPv6 interface: i. What is the hidden Hardware Address of the interface on Line #1? ii. What is the hidden subn

Explain about structure of management information, Question 1 a) What is a...

Question 1 a) What is a NMS? Question 2 Explain about Structure of Management Information Question 3 A)In which UDP port number does a protocol entity receive message?

It service support within the itil framework, Problem (a) IT Service Suppo...

Problem (a) IT Service Support within the ITIL framework is divided in a number of processes. Compare and contrast the following processes: i. Incident Management and Problem M

Non-repudiation and auditing, Proof that the sender forwards the message. I...

Proof that the sender forwards the message. It also prohibits the author of the code from falsely denying that he forward the message. This is achieved by record using the exact ti

Categories of controls-risk management, Categories of Controls Controlli...

Categories of Controls Controlling risk through mitigation, avoidance or transference is accomplished by implementing controls. There are 4 effective approaches to select the co

Firewalls-information security, Firewalls A firewall in an information s...

Firewalls A firewall in an information security program that prevents specific types of information from moving between the outside world and the inside world. The firewall may

Project, Network diagram for a mediacal care

Network diagram for a mediacal care

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