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

Local talk, LOCAL TALK Apple discovered the LAN technology that uses b...

LOCAL TALK Apple discovered the LAN technology that uses bus topology. Its interface is added with all Macintosh computers. It has very low speed i.e. 230.4Kbps. Also it is ch

Briefly explain the following security goals, (a) Briefly explain the fo...

(a) Briefly explain the following security goals provided by cryptography: confidentiality, authentication, integrity and non-repudiation. (b) State Kerckhoff's Princip

Project, project on ensuring data securities on cloud computing

project on ensuring data securities on cloud computing

Define checksum, The method used to check errors is checksum . In this m...

The method used to check errors is checksum . In this method data is treated as a sequence of integers and their arithmetic sum is calculated and the carry bits are added to the

Describe how ethernet deals with collisions, Problem (a) The IEEE 802 seri...

Problem (a) The IEEE 802 series of standards describe both the Physical and Data Link layers of their respective technologies. Two important standards are 802.3 and 802.5, respect

Define bridges, Bridges perform both in the data link layers and physical...

Bridges perform both in the data link layers and physical of LANs of same kind. They split a bigger network in to smaller segments. They have logic that accept them to store the

State the fermat-euler theorem, Question: (a) Prove that every positive...

Question: (a) Prove that every positive integer n can be factorized into a product of prime powers. (b) State the Fermat-Euler theorem as needed in the RSA system. (c) Us

Draw the waveform for an asynchronous transmission, QUESTION: (a) For ...

QUESTION: (a) For the bit stream 010011, sketch the waveforms for each of the code indicated. Assume that the signal level for a space in NRZ-L is positive; the signal level f

Use the chinese remainder theorem to evaluate x, Use the Chinese remainder ...

Use the Chinese remainder theorem to evaluate x from the following simultaneous congruences: x ≡ 1 (mod 2); x ≡ 2 (mod 3); x ≡ 3 (mod 5). Calculate gcd(14526, 2568). (

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