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

What is the use of digital certificate, Question: (a) What is the use ...

Question: (a) What is the use of digital certificate? (b) What is meant by a hierarchical trust model in a Public Key Infrastructure? How does the Pretty Good Privacy (PG

Cyber security, How to pretect my computer from attacking

How to pretect my computer from attacking

What is internet, The Internet is known as the set of networks connect...

The Internet is known as the set of networks connected by routers that are configured to pass traffic among any machine attached to any network in the set. By internet several

Error reporting mechanism (icmp), ERROR REPORTING MECHANISM (ICMP) INT...

ERROR REPORTING MECHANISM (ICMP) INTRODUCTION:  IP gives best-effort delivery. Delivery causes can be ignored; datagrams may be 'dropped on the ground'. Internet Control Me

Illustrate about tinysec protocol, Illustrate about TinySec Protocol T...

Illustrate about TinySec Protocol TinySec is implemented on the link layer and addresses security requirements of the resource staffed nodes in the WSN based on the link layer

Softbank theft of consumer data -information security, Example : Softbank –...

Example : Softbank – theft of consumer data for extortion Softbank of Japan offers broadband Internet services across Japan through 2 subsidiaries – Yahoo! BB and Softbank BB. I

Point to point transmission(ppp), Normal 0 false false fals...

Normal 0 false false false EN-US X-NONE X-NONE

Explain why spreadsheets are so useful, Question: Spreadsheet packages ...

Question: Spreadsheet packages are widely used in Business. a) Explain why spreadsheets are so useful. b) Spreadsheet files are sometimes saved for use by other software

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

Increasingly significant impact on society, Question: (a) African gove...

Question: (a) African governments are slowly shifting to more transparent ICT regulations. However, but limited spectrum availability remains a key barrier to sustaining lon

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