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

Difference between synchronous tdm and statistical tdm, Question (a) A CRC...

Question (a) A CRC is constructed to generate a 4-bit FCS for an 11-bit message. The divisor polynomial is X 4 + X 3 + 1 (i) Encode the data bit sequence 00111011001 using po

Network security in an organisation, Network security is an issue for compa...

Network security is an issue for companies regardless of whether they participate in electronic commerce; however, since most organizations have a Web site that allows some interac

Packet sniffers, PACKET SNIFFERS A packet network protocol analyzer is a...

PACKET SNIFFERS A packet network protocol analyzer is a network tool which collects copies of packets from network and analyzes them. It can give network administrator with valu

Implement security measures, Problem (a) Give two reasons for companie...

Problem (a) Give two reasons for companies to implement security measures. (b) What is the regulatory expectation regarding i. healthcare information, ii. financial

Describe types of communication impairments, Question : (a) "Pulse Code...

Question : (a) "Pulse Code Modulation (PCM), as used in telephony, samples a signal at 8 kHz using 256 quantization levels". Outline how this scheme works with the help of ske

Explain the term quality of service in networks, QUESTION (a) One of th...

QUESTION (a) One of the biggest drawbacks that GNS3 has is that it supports only the IOS images of routers. This means that users cannot emulate Cisco switches. Suggest two sol

Explain how ethernet deals with collisions, (a) Describe how CSMA/CD operat...

(a) Describe how CSMA/CD operates and explain how Ethernet deals with collisions. (b) Describe how the subsequent protocols work: i. ARP ii. DHCP iii. DNS iv. SMTP (c) The

Explain web defacement, QUESTION (a) Compare and contrast phishing and ...

QUESTION (a) Compare and contrast phishing and pharming attacks (b) Nowadays, web defacement may not always be visual (i) Explain web defacement (ii) What is the main

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