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

Define parity bit, PARITY BIT: A parity bit is an extra bit transmitt...

PARITY BIT: A parity bit is an extra bit transmitted with data item select to give the resulting bit odd or even parity. For example an even parity data packet 10100001 has p

TCP/ ip, Q1 (15 marks, 5 marks each part): This question has three parts: ...

Q1 (15 marks, 5 marks each part): This question has three parts: In a short paragraph (200-300 words) explain the fundamentals of Packet Switching and how it works. In a short pa

List vulnerabilities of using wep, Question: The Wired Equivalent Priv...

Question: The Wired Equivalent Privacy (WEP) standard was created in order to give wireless networks safety and security features similar to that of wired networks. (a) L

Elements of cryptosystems-cryptography, Elements of Cryptosystems Crypto...

Elements of Cryptosystems Cryptosystems is characteristically made up of algorithms, data handling techniques, and procedures which are combined in multiple ways to ensure confi

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

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

Risk determination, Risk Determination For purpose of relative risk asse...

Risk Determination For purpose of relative risk assessment, risk equals probability of vulnerability occurrence TIMES value MINUS percentage risk already controlled PLUS an elem

Explain the encryption model or symmetric cipher model, With explain the en...

With explain the encryption model the help of diagram. Symmetric cipher model uses the secret-key or a single-key for encryption/decryption purposes. It employs a symmetric encr

Briefly explain the contents of the needs analysis, QUESTION (a) Brief...

QUESTION (a) Briefly explain the contents of the Needs Analysis, which is step in the process of network design. (b) Describe on the three ways of improving the performan

CS, Discuss how developers should apply the following countermeasures to im...

Discuss how developers should apply the following countermeasures to improve the security of their code:

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