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

Fragmentation, FRAGMENTATION One method is to limit datagram size to s...

FRAGMENTATION One method is to limit datagram size to smallest MTU of any server. IP needs fragmentation i.e. datagrams can be divided into pieces to fit in network with small

[email protected], Re: Website Google Ranking Hello! Hope yo...

Re: Website Google Ranking Hello! Hope you are doing well. I discovered some major issues in your website which might be the cause for the Google Penalties and poor search ranki

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

Netfilter firewall, Netfilter Firewall Netfilter is the popular name f...

Netfilter Firewall Netfilter is the popular name for the packet filtering system installed by default in the Linux kernel. The filtering system can be used as a very effective

Malicious node detection mechanisms, Many applications are vulnerable to in...

Many applications are vulnerable to intrusion attacks and can provide misleading reports about misbehaving nodes. Some of the mechanisms under such a category include the Bayesian

Network security in an organisation, Network security is an issue for compa...

Network security is an issue for companies regardless of whether they participate in electronic commerce; however, since most organizations have a Web site that allows some interac

Why is this setup not secure, Question: a) You are using Active Directo...

Question: a) You are using Active Directory Users under Windows Server 2003 and Computers to configure user objects in your domain, and you are able to change the address and

CNSS Security model, "Using the CNSS Model, examine each of the cells and w...

"Using the CNSS Model, examine each of the cells and write a brief statement on how you would address the components respesented in that cell"

Issue-specific security policy (issp), Issue-Specific Security Policy (ISSP...

Issue-Specific Security Policy (ISSP) The ISSP addresses specific areas of technology, needs frequent updates and having statement on organization’s position on a particular iss

Distinguish between steganograhy and cryptography, Question: (a) Disti...

Question: (a) Distinguish between Steganograhy and Cryptography. (b) "Playfair cipher is more secure than Monoalphabetic cipher." Justify this statement. (c) Various ap

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