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

Systems-specific policy (syssp), Systems-Specific Policy (SysSP) SysSP...

Systems-Specific Policy (SysSP) SysSPs are codified as standards and procedures which are used when configuring or maintaining systems. Systems specific policies fall into 2 g

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

Management of classified data-risk management, Management of Classified Dat...

Management of Classified Data Management of classified data comprises of its storage, distribution, portability, and destruction of classified data. All information which is not

Secure routing protocols for wireless sensor networks, Q. Secure routing Pr...

Q. Secure routing Protocols for Wireless Sensor Networks? A secure routing information protocol enables effective implementation of authentication and integrity checking defens

Information security policy practices and standards, INFORMATION SECURITY P...

INFORMATION SECURITY POLICY PRACTICES AND STANDARDS Management from all the communities of interest should consider policies as basis for all information security efforts. Polic

Elliptic Curves, #questioAn elliptic curve y^2=x^3+ax+b(mod29) includes poi...

#questioAn elliptic curve y^2=x^3+ax+b(mod29) includes points P=(7, 15) and Q=(16, 13) a)Determine the equation of the crve b) Determine all values of x for which there is no point

Explain transposition ciphers and substitution cipher, What do you understa...

What do you understand by cryptanalysis? Discuss about the transposition ciphers substitution cipher, and onetime pads. The messages which are intended to transmit secretly and

Hybrid cryptography systems-cryptography, Hybrid Cryptography Systems Th...

Hybrid Cryptography Systems This makes use of different cryptography systems. Except digital certificates, pure asymmetric key encryption is not used extensively. Asymmetric enc

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

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