Compute the relative frequencies of each letter in a cipher

Assignment Help Basic Computer Science
Reference no: EM13756631

Question

In cryptography, a Caesar cipher, also known as Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number of positions down the alphabet. For example, with a left shift of 3, D would be replaced by A, E would become B, and so on. The method is named after Julius Caesar, who used it in his private correspondence.

The encryption step performed by a Caesar cipher is often incorporated as part of more complex schemes, such as the Vigenère cipher, and still has modern application. As with all single alphabet substitution ciphers, the Caesar cipher is easily broken and in modern practice offers essentially no communication security. Generally speaking, it is a great exercise to understand crypto, and for our purposes, it deals with various concepts for learning a new programming language.

The Caesar Cipher, the Multiplication Cipher and the Linear Cipher have one property in common. They all fall in the category of Monoalphabetic Ciphers: "Same plain letters are encoded to the same cipher letter." I.e. in the Caesar Cipher each "a" turned into "d", each "b" turned into "e", etc.

The following holds true for each of the above Ciphers: Although letters are changed the underlying letter frequencies are not! If the plain letter "a" occurs 10 times its cipher letter will do so 10 times. Therefore, ANY Monoalphabetic Cipher can be broken with the aid of letter frequency analysis.

To compute the relative frequencies of each letter in a cipher text simply count the occurrences of the letter in the text. Afterwards compare the letter frequencies with those of the English language (assuming that the cipher text stems from an English plain text). Remember that

a) The most frequent letter of the English language is "e" (with about 12%) followed by t,i,o,a,n,s,r which is very helpful to break the cipher text.

b) The longer the cipher text the better do the counted letter frequencies converge to the actual English plain letter frequencies.

Reference no: EM13756631

Questions Cloud

Compare leadership teams and quality improvement teams : Compare leadership teams and quality improvement teams. Briefly describe the various elements of strategy development. List the practices used to improve customer-supplier relationships
Bounded rationality : Research, then define, “Bounded Rationality” and give an example of when it’s played a part in your life. This is a two-page paper minimum, APA format. The title page, references and abstract do NOT count to the total. I expect TWO FULL PAGES in the ..
Explain role capitalism plays in corporate decision-making : Explain the role capitalism plays in corporate decision-making- Discuss if you believe it is possible for a company to cater to both its best interest and that of the consumer conjointly or if one always has to prevail. Justify your response.
Reference price for the evolution series locomotive engine : In 2005 GE released its Evolution Series locomotive engine. Estimated fuel savings were roughly 1,000,000 gallons per year. At the time of its release, GE and other competitors were selling numerous locomotives priced near $2 million. What is the ref..
Compute the relative frequencies of each letter in a cipher : The most frequent letter of the English language is "e" (with about 12%) followed by t,i,o,a,n,s,r which is very helpful to break the cipher text.
Create a report explaining the research process : A company is considering creating and selling a new type of cookies. Create a report explaining the research process that should be used by the company to make this decision. What is the research question? How would you design the research project? W..
What are the inputs to and outputs of a supply chain : You are hosting a tailgate party for forty people prior to the next home game for your university football team. The menu includes burgers with all of the fixings, brats, and ribs. You are responsible for procuring all the ingredients and the transpo..
Explain an efas table for your selected company : Prepare and explain an EFAS table for your selected company. Data presented in tables do not speak for themselves. Whenever you present the results of data analysis, you must interpret the data. What does it indicate? What does it mean? What are t..
Create a report describing the process needed to manufacture : In a 4- to 5-page Microsoft Word document, create a report describing the process needed to manufacture your computer. Include the following in your explanation: The layout needed to manufacture the computer

Reviews

Write a Review

Basic Computer Science Questions & Answers

  Software developments is for developers to analyze

The goal of real world software developments is for developers to analyze, design, program, and test complete applications that solve the needs of the customer. The iLab exercises you have been given will give you practice with the specific programmi..

  A topic relevant to current information

Select two articles on a topic relevant to current information security trends and describe its impact on business; assess the steps industry should take to address it. Formatting: APA style paper, double spaced, two pages, Cover page, reference ..

  Prove the set of all functions from a to b is countable

Let A = {0,1} and B be a countable set. Prove that the set of all functions from A to B is countable

  Identify the strengths and weaknesses of the nist programs

Identify the strengths and weaknesses of the NIST programs compared to the ISO standard.

  A motor vehicle maintenance center wants to improve serv

A motor vehicle maintenance center wants to improve its services by using database management systems (DBMS) and data mining. What tables are needed in such a database and how can it help improve their 2.2, 3.2services?

  Problem related to computer architecture

For snoopy bus control what will happen on CPU A for a line in the shared state if there is a miss on CPU A for another memory cell that also maps to that line you assume CPU A's cache is directed mapped.

  What window events can a program handle

What is the paintComponent method? How is it used in Java graphics? How does a program intentionally cause the paintComponent method to execute?

  The code be written by hand using a text editor

Demonstrate your ability to create a web site. Your web site should consist of at least 4 pages, a main page, an additional information page, a page containing form elements (such as a contact page), and one additional page of your choice.

  What is x after the following if-else statement is executed

What is x after the following if-else statement is executed? Use a switch statement to rewrite it and draw the flowchart for the new switch statement.

  Secure data access and encryption of a patientdatabase

OverviewIn this lab, you implemented policies that map to the Sarbanes-Oxley Act (SOX), the PaymentCard Industry Data Security Standard (PCI-DSS), and the Health Insurance Portability andAccountability Act (HIPAA). You ensured secure data acce..

  Write the complete myfnc function to return the value 1

Write the complete myfnc function to return the value 1 if they are equal and return the value 0 if they are not equal.

  Mips assembly program

MIPS Assembly Program: Help writing this function

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