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

Attacks on cryptosystems-cryptography, Attacks on Cryptosystems Attacks a...

Attacks on Cryptosystems Attacks are attempts to achieve unauthorized access to secure communications have characteristically used brute force attacks. Attacker may alternatively

Plaintext, how to encryt the data in plaintext cipher

how to encryt the data in plaintext cipher

Vulnerability identification-risk management, Vulnerability Identification ...

Vulnerability Identification Specific avenues threat agents can exploit to attack an information asset are known as vulnerabilities. Examine how each threat can be generated and

Evaluate the sample correlation between y and z, Question: (a) Data on ...

Question: (a) Data on four variables are stored in a file called file1.dat. The first line of the file is the variable names f, x, y and z. Give the R commands to (i) read t

Computer Security, I have an assignment of Computer Security to submit. Wil...

I have an assignment of Computer Security to submit. Will you guys help me making my assignment???

Provide the network configuration, QUESTION: a) Below is a capture of a...

QUESTION: a) Below is a capture of an Ethernet II frame which has an IPv4 packet and a segment. Provide the source MAC address in hexadecimal; the source IP address, the length

Encapsulation, ENCAPSULATION Network interface layer adds IP datagram ...

ENCAPSULATION Network interface layer adds IP datagram as data area in hardware frame. Hardware ignores IP datagram message format. Standards for encapsulation defines details

Technology, how can you enter the ASVAB practice test on line?

how can you enter the ASVAB practice test on line?

Information asset classification-risk management, Information asset classif...

Information asset classification-risk management A number of organizations have data classification schemes (for instance confidential, internal, public data). The classificat

Risk control strategies-risk management, Risk Control Strategies Once th...

Risk Control Strategies Once the ranked vulnerability risk worksheet has created, they should choose one of following 4 strategies to control each risk: •    Apply safeguards wh

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