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

Define repeater, Repeater known as regenerator ; it is an electronic mac...

Repeater known as regenerator ; it is an electronic machine that performs only at physical layer. It gets the signal in the network before it becomes loss or weak, recreates the

Social network development in java , Social Network development in Java: ...

Social Network development in Java: Project Title: SUGGESTLOCAL (Nov 2006-April 2007) Role             : Developer Domain        : Social Network Client          :

Cyber security, How to pretect my computer from attacking

How to pretect my computer from attacking

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

Cipher methods-cryptography, Cipher Methods There are 2 methods of encry...

Cipher Methods There are 2 methods of encrypting plaintext: • Bit stream method – every bit in the plaintext bit is transformed into a cipher bit one bit at a time. • Block cip

Plain-text using play-fair encryption, What is one-time pad for encryp...

What is one-time pad for encryption?  Describe how it offers both Confusion and Diffusion. Using the letter encoding discussed in class (along with one-time

Computer security, Implementing an effective online authentication scheme i...

Implementing an effective online authentication scheme in practice faces many challenges. Systems with highly sensitive data often require multifactor authentication. But, requirin

Wireless security tools, WIRELESS SECURITY TOOLS An organization which s...

WIRELESS SECURITY TOOLS An organization which spends its time securing wired network and leaves wireless networks to operate in any manner is opening itself up for security brea

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