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

Illustrate the term file carving, QUESTION (a) Illustrate the term fil...

QUESTION (a) Illustrate the term file carving. (b) What are the basic three main techniques for image steganography? (c) Distinguish between vector graphics and raster

State the fermat-euler theorem, Question: (a) Prove that every positive...

Question: (a) Prove that every positive integer n can be factorized into a product of prime powers. (b) State the Fermat-Euler theorem as needed in the RSA system. (c) Us

Explain symmetric and asymmetric encryption system, Question 1: (a) Dif...

Question 1: (a) Differentiate between symmetric and asymmetric encryption system. (b) Describe how a digital signature is created. (c) Explain briefly what SSL (secure so

Local talk, LOCAL TALK Apple discovered the LAN technology that uses b...

LOCAL TALK Apple discovered the LAN technology that uses bus topology. Its interface is added with all Macintosh computers. It has very low speed i.e. 230.4Kbps. Also it is ch

Which authorization model could be ideal, Question: (a) Your office ad...

Question: (a) Your office administrator is being trained to take server backups. Which authorization model could be ideal for this situation: MAC, DAC or RBAC? Justify your a

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

Understanding a business model of a spammer, The first and foremost need of...

The first and foremost need of  any business is a role to perform for its client base, and for the spammer this will typically be the role of advertising products which, due to the

Arp responses, ARP RESPONSES Let's search out how does a computer know...

ARP RESPONSES Let's search out how does a computer know whether an incoming frame have an ARP message. The type field in the frame header defines that the frame contain an ARP

Transmission errors in networking, TRANSMISSION ERRORS:  Transmission...

TRANSMISSION ERRORS:  Transmission exceptions may happen due to different causes for example power surges or interference may delete data during transmission. In result of wh

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