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

Find the possible deciphering transformations, Question: (a) A string o...

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 ha

Need for security-information security, NEED FOR SECURITY Primary missio...

NEED FOR SECURITY Primary mission of information security to ensure that the systems and contents stay the same If no threats, could focus on improving the systems, resulting in

Encryption key size-cryptography, Encryption Key Size When using ciphers...

Encryption Key Size When using ciphers, the size of crypto variable or key is quite important as the strength of many encryption applications and cryptosystems were measured by

Basic types of agent in order of increasing generality, Question 1: (a)...

Question 1: (a) Define Artificial Intelligence. (b) Briefly describe the categories for the definition of Artificial Intelligence. (c) Identify the four basic types of

Application gateways / firewall-information security, Application Gateways ...

Application Gateways / firewall The application level firewall is installed on a dedicated computer; also called as a proxy server. These servers can store the recently accessed

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

Calculate the false rejection, Divide the user data into 6 equal sets. Use ...

Divide the user data into 6 equal sets. Use the first set for the enrollment phase of your system, and the rest for the verification phase. Use the following formula to calculate t

Explain briefly how go-back-n operates, Question: a) There are two basi...

Question: a) There are two basic approaches to dealing with errors in the presence of pipelining. One way is Go-Back-N and the other strategy is Selective Repeat. i. Explain

Explain possible attacks on rsa encryption, Problem (a) Describe RSA a...

Problem (a) Describe RSA algorithm with an example. (b) Answer the following RSA encryption, given the values of the primes are: p = 17, q = 11 and choosing e = 7. (c)

Define secure socket layer (ssl), Secure Socket Layer (SSL) accepts a combi...

Secure Socket Layer (SSL) accepts a combination of asymmetric and symmetric (public-key) encryption to accomplish integrity, confidentiality, authentication and non-repudiation for

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