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

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

Short term scheduler, Short term Scheduler function , also shown as a disp...

Short term Scheduler function , also shown as a dispatcher runs most frequently, and creates the finest-grained decision of which program could run next. This scheduler is called

Determine the round trip time, QUESTION a) Determine the RTT (round tr...

QUESTION a) Determine the RTT (round trip time) between a client requesting a web page of 1024 bytes in size from an internal web server on a 100 Base-T Ethernet. Consider a o

Systems development life cycle security-information security, The Role of t...

The Role of the Investigation The first phase, investigation is the most significant. What problem is the system being developed to solve? During investigation phase, objectives

Assignment, for making the assignment

for making the assignment

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.

Guided media, Guided Media These are those that give a conduit from on...

Guided Media These are those that give a conduit from one machine to another that add twisted-pair, fiber-optic cable and coaxial cable. A signal traveling along any of these

Explain the purpose of the dr and bdr, QUESTION a) Compare and contras...

QUESTION a) Compare and contrast between static and dynamic routing. b) What are the merits (five merits) and limitations (3 limitations) of using Open Shortest Path First

Virtual terminal protocol vtp, Write down the short notes on VTR.  Communic...

Write down the short notes on VTR.  Communication between different types of the equipment and software is made possible by making use of the networks. Full-screen text editor is 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