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

Policy management-information security, POLICY MANAGEMENT Policies should...

POLICY MANAGEMENT Policies should be managed as they constantly change. Good policy development and maintenance make a more resilient organization. All policies undergo tremendou

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

Assignment, Hello i have submitted an assignment and i am still waiting to ...

Hello i have submitted an assignment and i am still waiting to know if it has been accepted or not the ref number is TicketID: EM201381BRY525CN, the due date is for monday 27th of

Describe how the encapsulated security header protocol, Question: (a) ...

Question: (a) Give 2 benefits of using IPsec. (b) IPSec uses two protocol for security: Authentication Header protocol (AH) and the Encapsulated Security Header Protocol (

Ids-information security, IDS Intrusion is a attack on information assets...

IDS Intrusion is a attack on information assets in which instigator attempts to gain entry into or disrupt normal system with harmful intent Incident response is an identificatio

Location to e-mail messages are saved, In the e-mail system, where the e-ma...

In the e-mail system, where the e-mail messages are saved and why? E-mail messages are saved in user’s private electronic mailbox. A mailbox refers to a local/domestic hard drive c

Question, Describe the process a proposed standard goes through to become a...

Describe the process a proposed standard goes through to become an RFC

Digital signatures, Digital Signatures Digital Signatures are encrypted ...

Digital Signatures Digital Signatures are encrypted messages which can be proven mathematically to be authentic. These are created in response to rising requirement to verify in

Describe the time limit problem, Problem: (a) Use a simple example to ...

Problem: (a) Use a simple example to explain what is meant by a finite state machine. (b) Describe the time limit problem in an interrupt-driven system. (c) A certain m

Venn Diagram Problem, Students were asked about search engine they used.90 ...

Students were asked about search engine they used.90 of them said they used google chrome,70 used Internet Explorer,40 used Mozilla Firefox,30 used Google Chrome and Internet Explo

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