Placeholders for the plaintext characters, 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:- Placeholders for the plaintext characters

Pinging a web server, Ask quIf you are pinging a web server from a user’s c...

Ask quIf you are pinging a web server from a user’s client PC, how might the statistical information provided by ping be useful to you?estion #Minimum 100 words accepted#

Explain how ftp works, QUESTION (a) FTP is a protocol used for the de...

QUESTION (a) FTP is a protocol used for the delivery of files across networks. Explain how FTP works (support your answer with a diagram). (b) How does TCP perform the gi

Encryption, How safe is the encryption of virtual private networks?

How safe is the encryption of virtual private networks?

Management of classified data-risk management, Management of Classified Dat...

Management of Classified Data Management of classified data comprises of its storage, distribution, portability, and destruction of classified data. All information which is not

Define network, A Network is described as a system for connecting compu...

A Network is described as a system for connecting computers using a single transmission technology. The computers can interact with each other in a network. They can receive an

Mastering the complexity of network system, To master the complexity one mu...

To master the complexity one must apply the given points. CONCENTRATE IN UNDERSTANDING THE CONCEPTS: Instead of details of wires used to connect computers to a specif

Network simplex method, QUESTION: (a) Briefly explain the steps invol...

QUESTION: (a) Briefly explain the steps involved in Network Simplex Method. (b) What data structures you would expect in the Network Simplex Method. Show the data struct

Cost benefit analysis (cba)-information security, Cost Benefit Analysis (CB...

Cost Benefit Analysis (CBA) The common approach for information security controls is economic feasibility of implementation. CBA is begun by evaluating the worth of assets which

What do you understand by the term integrity, Question: (a) What do yo...

Question: (a) What do you understand by the term "integrity"? (b) Which type of attack denies authorized users access to network resources? (c) You have discovered tha

Functional areas in network management, Question 1 a) Explain how CSMA...

Question 1 a) Explain how CSMA/CD works. b) Describe the term "exponential back-off". c) Describe the differences between "circuit switching" and "packet switching". d) Th

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