ciphertext, Computer Network Security

Assignment Help:
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 generalised Caesar cipher where the following rule computes a character ci in the cipher text from a character pi in the plain text:

ci = E(pi) = pi + d

where d is a positive integer.

Find the number d and the plain text. Hint: use a table of English letter frequencies. This information can be found on the Internet.

c) Now consider the following cipher text:

homlox prv hetorx orxolxpersorx

A more general substitution cipher has been used. Recall that this means that every letter of the alphabet appearing in the plain text is replaced with another unique letter of the alphabet. For example, the letter ''a'' could be mapped into ''h'', the letter ''b'' into ''x'' etc. The ciphertext then simply consists of these mapped letters.
Work out the original plain text message, using the following approach:

(i) Write a line of dashes ("_") as placeholders for the plaintext characters corresponding to each letter in the above cipher text. Make sure you also mark the spaces between the different words as they will give you clues as soon as you know some of the letters.

(ii) Using the English letter frequency table, find the letter which the letter "e" is most likely to be replaced with. Use this to replace some of the "_" by the letter "e" (simply copy the last line you wrote and then replace).

Related Discussions:- ciphertext

Describe the process of components identification, Probelm 1: Give the ...

Probelm 1: Give the History and Evolution of Wireless Communication System. Complete explanation Probelm 2: Describe the process of Components Identification and cal

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

Compare the suitability and properties of isdn and adsl, Question : An a...

Question : An aircraft manufacturing company is considering linking the network of one of its offices to the network of its Headquarter using either xDSL or ISDN. i. Compare

Define byte stuffing, Sometimes the special character may see in data and a...

Sometimes the special character may see in data and as a part of data they will be misinterpreted as packet data. The solution to this cause is Byte stuffing.   In general to

Explain any two types of security policies, Question 1 Explain any two typ...

Question 1 Explain any two types of security policies Question 2 What is security attack? Explain with examples Question 3 Explain different characteristics that i

Star topology, In Star topology all computers are connected using a cen...

In Star topology all computers are connected using a central device known as hub. Star networks are one of the most general computer network topologies. In its simplest way, a

Cryptographic hash functions, (a) (i) Bob has public RSA key (n = 77, e...

(a) (i) Bob has public RSA key (n = 77, e = 7). Show that Bob's private key is (d = 43). (ii) Alice wants to send the message m = 13 to Bob. She encrypts the message usi

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

Define broadcasting , Broadcasting is the distribution of video and audio...

Broadcasting is the distribution of video and audio content to a whole audience via any audio or visual mass communications medium, but generally one using electromagnetic radiat

Legal, LEGAL, ETHICAL AND PROFESSIONAL ISSUES To minimize liabilities an...

LEGAL, ETHICAL AND PROFESSIONAL ISSUES To minimize liabilities and reduce risks, information security practitioner should: •    to understand current legal environment •    to s

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