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

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

What is triple key management scheme, Q. What is Triple Key Management Sche...

Q. What is Triple Key Management Scheme? The triple key management mechanism provides optimum security by enabling the use of two pre-deployed keys for each of the WS nodes, an

Risk management discussion points, Risk Management Discussion Points Org...

Risk Management Discussion Points Organizations should define level of risk it can live with Risk appetite: it defines quantity and nature of risk which organizations are wil

Security and basics steps in writing thesis, how can i start thesis? Please...

how can i start thesis? Please mention so of examples?

Limitations of ethical dilemma, The best results obtained in the PIIT class...

The best results obtained in the PIIT classes have been when the technique has been used in tutorial groups, rather than have students submit individual reflections on particular c

Describe the functioning of cloud computing, Question 1:  Describe the ...

Question 1:  Describe the functioning of cloud computing. Question 2: Discuss on "Platform as a Service". Question 3: Discuss the steps involved in effective co

Difference between a class profile and a child profile sheet, QUESTION ...

QUESTION (a) Mention two attitudes of a carer towards an inspector that could lead to negative outcomes (b) Give two performance indicators of Early Childhood Education that

Ip datagram format, IP DATAGRAM SIZE:  Datagrams may have different si...

IP DATAGRAM SIZE:  Datagrams may have different sizes i.e. Header area is generally fixed (20 octets) but can have various options. Data area may contain between 1 octet and 6

Explain what is software debouncing, Question : (a) How does a 2-key r...

Question : (a) How does a 2-key rollover differ from the N-key rollover? (b) Why is isolation so important in interfacing? (c) Explain what is software debouncing.

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