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

Address resolution with message exchange, ADDRESS RESOLUTION WITH MESSAGE E...

ADDRESS RESOLUTION WITH MESSAGE EXCHANGE An alternative to local calculation is a distributed function. A computer that requires to find an address transmits a message across

Discuss the importance of ontologies in agent communication, Question 1...

Question 1 The speech act theory is used as the model for communication among computational agents. Locution, illocution, and perlocution are the 3 aspects of this theory Using

Programming, For this assignment you will create a program called MMWordFix...

For this assignment you will create a program called MMWordFix (Multi-Mode WordFix). This program prompts the user to select one of three word filters (uppercase, lowercase, encryp

Html, how to link html with a data base

how to link html with a data base

Basic types of agent in order of increasing generality, Question 1: (a)...

Question 1: (a) Define Artificial Intelligence. (b) Briefly describe the categories for the definition of Artificial Intelligence. (c) Identify the four basic types of

Logic bombs - attacks information security, Example 3: Logic bombs In th...

Example 3: Logic bombs In the year 2000, Timothy Lloyd was found responsible of causing $10 million and $12 million of damage to Omega Engineering, an American company specializ

Draw the full network diagram, Problem (a) Below is a capture of an E...

Problem (a) Below is a capture of an Ethernet II frame which contains an IPv4 packet and a TCP segment. The second screen capture is from the data portion of the frame.

Operation of the signature based intrusion detection system, Question : ...

Question : (a) State whether the following statement is FALSE or TRUE: It is always better to have various access points to the Internet so that if a hacker takes one down you

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