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

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

Marketing, what are the participant of marketing channal?

what are the participant of marketing channal?

Internet protocol(ip), Internet Protocol IP Gives computer-to-comp...

Internet Protocol IP Gives computer-to-computer communication. Host and receiver addresses are computers. This is also known machine-to-machine communication.

Briefly list functions of a public key infrastructure, Question: (a) Wh...

Question: (a) What is the major problem with public key encryption when compared to symmetric key encryption? (b) Consider the following protocol for communication between t

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

Evaluate the percentage availability of the network, QUESTION a) "Two ...

QUESTION a) "Two of the key attributes of an enterprise network is that it have to be multi-platform and multisite." Decribe what you understand by this statement. b) A

Ciphertext, Encode the following plaintext, using the Caesar cipher: ...

Encode the following plaintext, using the Caesar cipher: LORD OF THE RINGS b) The following ciphertext jw njbh lxmn cx kanjt has been encoded using a

What is information security, What is information security Information s...

What is information security Information security protects information (and facilities and systems which store, use and transmit it) from a broad range of threats, in order to p

Describe how ipsec provides data source authentication, Question: (a) ...

Question: (a) Describe how IPSec provides data source authentication. (b) Which protocol can be used to provide limited traffic analysis confidentiality? Why is it "limite

Network-based ids (nids), Network-Based IDS (NIDS) A NIDS resides on com...

Network-Based IDS (NIDS) A NIDS resides on computer or appliance connected to segment of an organization’s network and looks for signs of attacks. While examining packets, a NID

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