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

What is the main security vulnerability of ipv4, Question: (a) What is...

Question: (a) What is the main security vulnerability of IPv4? (b) Which protocol can be used for secure remote login? (c) Distinguish between the transport and tunnel

What is the size of the initialization vector n wpa, Question : Wi-Fi p...

Question : Wi-Fi protected access (WPA) was specified by the Wi-Fi alliance with the primary aim of enhancing the security of existing 802.11 networks. However, WPA was only a

Network protocol hierarchy , This assignment aims to enhance students' unde...

This assignment aims to enhance students' understanding of the network protocol hierarchy and flow control and error control techniques by implementing a sliding window protocol in

ISDN, Explain the architecture of ISDN.....?

Explain the architecture of ISDN.....?

Military and space technology, crack the secret message and explain how the...

crack the secret message and explain how the code works. The clue is that it has something to do with the computer keyboard. J-Q-H-6 Q-E-F-Q-H-D-3-W 8-H 5-Y-3 7-W-3 9-R--D-9-J

What is border gateway protocol, Border Gateway Protocol It is a proto...

Border Gateway Protocol It is a protocol needed to advertise the set of networks that can be achieved within an autonomous machine. BGP activates this information to be shared

X.509, Consider the details of the X.509 certificate shown below. a. Identi...

Consider the details of the X.509 certificate shown below. a. Identify the key elements in this certificate, including the owner''s name and public key, its validity dates, the nam

Growth of lan technology, GROWTH OF LAN TECHNOLOGY The production of s...

GROWTH OF LAN TECHNOLOGY The production of shared communication channels (LANs) started in 1960s and early 1970. The basic idea behind was to reduce the number of connectio

802.11 wireless lans and csma/ca, 802.11 WIRELESS LANs AND CSMA/CA:  ...

802.11 WIRELESS LANs AND CSMA/CA:  IEEE 802.11 is standard wireless LAN that needs radio signals at 2.4GHz. Its speed is 11Mbps. The older computers use radio signals at data

Vulnerability scanners, VULNERABILITY SCANNERS Active vulnerability scan...

VULNERABILITY SCANNERS Active vulnerability scanners scan networks for detailed information, it initiate traffic to determine security holes. This scanner identifies usernames a

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