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

Intrusion detection and classification, i want to detec and classify networ...

i want to detec and classify network anomaly detection based on KDD99 data set using swarm intelligence

Packet filtering firewall-stateless packet filtering, Stateless Packet Filt...

Stateless Packet Filtering Stateless or static packet filtering is the most straightforward kind of packet filtering that allows or disallows data transfer based on the addres

What are the main objectives of a risk analysis, QUESTION 1 Risk ana...

QUESTION 1 Risk analysis helps companies prioritize their risks and shows management the amount of money that should be applied to protecting against those risks in a sensib

Important features of application layer, Describe the important features of...

Describe the important features of application layer. The features of the application layer are as follows. 1. Efficient User Interface Design is explained below: Appli

Important network security services, Question: (a) Consider that you en...

Question: (a) Consider that you enter the given URL in the address bar of a popular web client and that both the client and server accepts HTTP version 1.1. i. What can be t

Define full-duplex., A  full-duplex (FDX) , accepts communication in both...

A  full-duplex (FDX) , accepts communication in both ways, and, unlike half-duplex, accept this to occur simultaneously. Land-line telephone networks are full-duplex, since they

Use the chinese remainder theorem to evaluate x, Use the Chinese remainder ...

Use the Chinese remainder theorem to evaluate x from the following simultaneous congruences: x ≡ 1 (mod 2); x ≡ 2 (mod 3); x ≡ 3 (mod 5). Calculate gcd(14526, 2568). (

Why is this setup not secure, Question: a) You are using Active Directo...

Question: a) You are using Active Directory Users under Windows Server 2003 and Computers to configure user objects in your domain, and you are able to change the address and

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