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

Summarises the firewall protocols, Your rules should ensure that Internet a...

Your rules should ensure that Internet access will be restricted to the following: Only the following services will be permitted as OUTBOUND traffic (to the Internet from the DM

Illustrate about tinysec protocol, Illustrate about TinySec Protocol T...

Illustrate about TinySec Protocol TinySec is implemented on the link layer and addresses security requirements of the resource staffed nodes in the WSN based on the link layer

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

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

Calculate euler totient function value, (a) Explain the importance of the ...

(a) Explain the importance of the Euler Totient function in Cryptography. Calculate Euler Totient function value, φ(1280). (b) Explain the role of the Authentication Server (

Extended euclidean algorithm, (a) Using the extended Euclidean algorithm, ...

(a) Using the extended Euclidean algorithm, find the multiplicative inverse of 504 mod 67. (b) Decrypt the following ciphertext, which has been encrypted using Caesar cipher:

Draw the network layout, Question : a) Below is a capture of an Etherne...

Question : a) Below is a capture of an Ethernet II frame which contains an IPv4 packet and a TCP segment. Give the source MAC address for the frame in hexadecimal; the source I

Web accessibility initiative standards, Australian government sites were ma...

Australian government sites were mandated to conform to at least single 'A' level of the World Wide Web Consortium (W3C) Web Accessibility Initiative (WAI) standards, by the end of

Categories of controls-information security, Categories of Controls Cont...

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

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