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

Udp- datagram transport service, UDP- DATAGRAM TRANSPORT SERVICE INT...

UDP- DATAGRAM TRANSPORT SERVICE INTRODUCTION:  UDP is the one of the transport protocols in TCP/IP protocol suite. UDP protocol accepts applications on the computers to

Ipv6 datagram format, IPV6 DATAGRAM FORMAT It is given in the figure b...

IPV6 DATAGRAM FORMAT It is given in the figure below:

Identify possible controls-information security, Identify Possible Controls...

Identify Possible Controls For each threat and linked vulnerabilities which have residual risk, create primary list of control ideas. Residual risk is the risk which remains to

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

Encryption key size-cryptography, Encryption Key Size When using ciphers...

Encryption Key Size When using ciphers, the size of crypto variable or key is quite important as the strength of many encryption applications and cryptosystems were measured by

Using Technology as Experience Framework, Write a two to three (2-3) page p...

Write a two to three (2-3) page paper in which you: Explain how the Web user interfaces help donors to make decisions. Relate the emotional thread demonstrated in the case study to

Discuss five alternative testing techniques, QUESTION Testing of a Busi...

QUESTION Testing of a Business Continuity Plan (BCP) does not need to be costly or to interrupt the daily operations of the business. The result of the test should also be look

Research paper, how much would you charge for minimum 20 pages

how much would you charge for minimum 20 pages

Describe the functionality of a router, QUESTION: (a) Explain, with the...

QUESTION: (a) Explain, with the aid of a diagram, a Star topology of a network of your choice. (b) Illustrate on the use of a MAN and give an example of one. (c) Describe

Summarises the firewall protocols, Your rules should ensure that Internet a...

Your rules should ensure that Internet access will be restricted to the following: Only the following services will be permitted as OUTBOUND traffic (to the Internet from the DM

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