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

Access control devices-cryptography, ACCESS CONTROL DEVICES Successful a...

ACCESS CONTROL DEVICES Successful access control system includes number of components, which depends on system’s requirements for authentication and authorization. Powerful auth

Innovative nature of triple key management, Innovative nature of triple key...

Innovative nature of triple key management The triple key management scheme provides secure services by combining different techniques whic contribute to the security and priv

Reason for multiple topologies, REASON FOR MULTIPLE TOPOLOGIES Every t...

REASON FOR MULTIPLE TOPOLOGIES Every topology has disadvantages and advantages, which are described below: IN A RING:  It is simple to coordinate access to other dev

Calculate alpha and beta value caesar cipher, Task 1 a. Consider the t...

Task 1 a. Consider the table showing the relative frequencies of letters in English. Arrange the frequencies from largest to smallest, and make a cumulative plot, using Exc

Benchmarking-information security, Benchmarking An alternative approach to...

Benchmarking An alternative approach to risk management is Benchmarking. It is process of seeking out and studying practices in other organizations which one’s own organization de

Internet protocol(ip), Internet Protocol IP Gives computer-to-comp...

Internet Protocol IP Gives computer-to-computer communication. Host and receiver addresses are computers. This is also known machine-to-machine communication.

Cyber security, How to pretect my computer from attacking

How to pretect my computer from attacking

Network management system, Question (a) Draw a typical hybrid star-rin...

Question (a) Draw a typical hybrid star-ring topology paying attention to how the clients and switching hubs are connected. (b) State 3 main differences between a router

Collision detection, COLLISION DETECTION The signals from two devices ...

COLLISION DETECTION The signals from two devices will interfere with each other and the overlapping of frames is known a collision. It does not cause to the hardware but data

Malicious node detection mechanisms, Many applications are vulnerable to in...

Many applications are vulnerable to intrusion attacks and can provide misleading reports about misbehaving nodes. Some of the mechanisms under such a category include the Bayesian

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