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 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

Keystroke-based access control model, Suppose you are working for one of th...

Suppose you are working for one of the leading credit reporting agencies that manages users' credit rating info with different financial institutions.  The company wishes to implem

Innovative nature of triple key management, Innovative nature of triple key...

Innovative nature of triple key management The triple key management scheme provides secure services by combining different techniques whic contribute to the security and priv

Distinguish between a mobile agent state and code, Question: (a) Disti...

Question: (a) Distinguish between a mobile agent "state" and "code". (b) Differentiate between "weak" and "strong" mobility. (c) Mobile agent systems are known to have

Ip Datagram, Size of Option field of an ip datagram is 20 bytes. What is th...

Size of Option field of an ip datagram is 20 bytes. What is the value of HLEN? What is the value in binary?

Access control list, Scenario: A network with individual hosts (really, vir...

Scenario: A network with individual hosts (really, virtual machines) can run HTTP (web) servers that are available to the outside. (Here, available means the ability to read and wr

Project, project on ensuring data securities on cloud computing

project on ensuring data securities on cloud computing

Security clearances-information security, Security Clearances For a secu...

Security Clearances For a security clearance in organizations each data user should be assigned a single level of authorization indicating classification level. Before approachi

Techniques for combating spam mails, Techniques for combating Spam mails ...

Techniques for combating Spam mails Many anti spam products are commercially available in market. But it should also be noted that no  one technique is a complete solution to

Backup, types of firewall and backup

types of firewall and backup

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