User Account

All Pages

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

Hypothetical reliable data transfer protocol, Hypothetical reliable data tr...

Hypothetical reliable data transfer protocol: A jumping window based Go-back-N  ARQ protocol for file transfer using UDP as the transport protocol: In this protocol, a window o

Imap and pop functions, How does the POP functions? What are the advantages...

How does the POP functions? What are the advantages/benefits of IMAP over POP? POP stands for Post Office Protocol, version 3 (POP3) is one of the easiest message access protoc

Minimum cost flow problem, QUESTION (a) A convex flow problem is a no...

QUESTION (a) A convex flow problem is a non linear network flow problem. Explain how a convex flow problem could be transformed into a Minimum Cost Flow problem. (b) Exp

Websphere administrator, Websphere Administrator: Working as Webspher...

Websphere Administrator: Working as Websphere Administrator in the department called DART (Database Architecture Re-Engineering and Tuning). The major responsibilities are t

Address resolution with message exchange, ADDRESS RESOLUTION WITH MESSAGE E...

ADDRESS RESOLUTION WITH MESSAGE EXCHANGE An alternative to local calculation is a distributed function. A computer that requires to find an address transmits a message across

Distinguish between authorization and authentication, Question : (a) D...

Question : (a) Distinguish between authorization and authentication. (b) SSO (Single Sign On) implies a user logs in once and can access resources for a defined period of

Describe phishing attacks, QUESTION (a) (i) Describe Phishing attacks. ...

QUESTION (a) (i) Describe Phishing attacks. (ii) Distinguish between Phishing and Spear Phishing attacks. (b) Describe two instances where an attacker sniffing on a netwo

Issue specific security policy, Why an organization need the issue specific...

Why an organization need the issue specific security policy

Arp message format, ARP MESSAGE FORMAT Although the ARP data packet fo...

ARP MESSAGE FORMAT Although the ARP data packet format is sufficiently general to allow hardware addresses and arbitrary protocol. ARP is almost usually used to bind a 32-bit

Difference between a class profile and a child profile sheet, QUESTION ...

QUESTION (a) Mention two attitudes of a carer towards an inspector that could lead to negative outcomes (b) Give two performance indicators of Early Childhood Education that

Write Your Message!

Captcha
Order Assignment

Featured Services

Order Now

Popular Subjects

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!

Submit Assignment

Academics

Major Subjects

Majors

Get In Touch

whatsapp: +91-977-207-8620

Phone: +91-977-207-8620

Email: [email protected]

TERMS & POLICIES

HELP & SUPPORT

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd