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

Which authorization model could be ideal, Question: (a) Your office ad...

Question: (a) Your office administrator is being trained to take server backups. Which authorization model could be ideal for this situation: MAC, DAC or RBAC? Justify your a

Wireless local area network, a) Wireless local area network (WLAN) technol...

a) Wireless local area network (WLAN) technologies constitute a fast-growing market introducing the flexibility of wireless access into office, home, or production environments. G

Backup, types of firewall and backup

types of firewall and backup

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

Explain the concept of zero knowledge proofs, (a) Describe the concept of ...

(a) Describe the concept of zero knowledge proofs. Give a practical example. (b) Explain how a one way hash function works. (c) What are message authentication codes? (d)

Reason for multiple topologies, REASON FOR MULTIPLE TOPOLOGIES Every t...

REASON FOR MULTIPLE TOPOLOGIES Every topology has disadvantages and advantages, which are described below: IN A RING:  It is simple to coordinate access to other dev

Representation of a tcp header, (a) Figure is a representation of a TCP hea...

(a) Figure is a representation of a TCP header. For each of the fields lettered from A to G, state the name of the field and provide a brief explanation for the function of each fi

Ip datagram format, IP DATAGRAM SIZE:  Datagrams may have different si...

IP DATAGRAM SIZE:  Datagrams may have different sizes i.e. Header area is generally fixed (20 octets) but can have various options. Data area may contain between 1 octet and 6

Configure a router from command line interface, QUESTION (a) Describe ...

QUESTION (a) Describe the difference between static routing and dynamic routing algorithms. (b) List four functions that are performed by the Cisco IOS software during b

Computer fundamentals, Ask You have been asked by a new client to assist i...

Ask You have been asked by a new client to assist in setting up a new computer for her coffee shop. She has just purchased the newest Apple computer from an online site. Should wou

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