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

Arrangement of self-learning switches, QUESTION a) Consider the speed ...

QUESTION a) Consider the speed of propagation of an electrical signal is same to 2x10 8 m/s, evaluate the ratio of the propagation delay to the transmit time for the given typ

Datagram reassembly, DATAGRAM REASSEMBLY Recreation of original datagr...

DATAGRAM REASSEMBLY Recreation of original datagram is known as reassembly. Ultimate receiver acts reassembly as given below.Fragments can reach out of order. Header bit check

Topology, What is the concept of topology?

What is the concept of topology?

Calculate the false rejection, Divide the user data into 6 equal sets. Use ...

Divide the user data into 6 equal sets. Use the first set for the enrollment phase of your system, and the rest for the verification phase. Use the following formula to calculate t

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

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

Explain symmetric and asymmetric encryption system, Question 1: (a) Dif...

Question 1: (a) Differentiate between symmetric and asymmetric encryption system. (b) Describe how a digital signature is created. (c) Explain briefly what SSL (secure so

Risk determination, Risk Determination For purpose of relative risk asse...

Risk Determination For purpose of relative risk assessment, risk equals probability of vulnerability occurrence TIMES value MINUS percentage risk already controlled PLUS an elem

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

Growth of lan technology, GROWTH OF LAN TECHNOLOGY The production of s...

GROWTH OF LAN TECHNOLOGY The production of shared communication channels (LANs) started in 1960s and early 1970. The basic idea behind was to reduce the number of connectio

Compare the suitability and properties of isdn and adsl, Question : An a...

Question : An aircraft manufacturing company is considering linking the network of one of its offices to the network of its Headquarter using either xDSL or ISDN. i. Compare

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