Write a program to decrypt encrypted messages, Programming Languages

Assignment Help:

You are working for a cryptography department, where one of your jobs is to decipher intercepted messages that have been encrypted using a book cipher. The messages are sent by different people, each of whom writes their plaintext in a different language to confuse any attempt to decipher the messages. But this has made them a little too confident, and you have discovered a very useful secret: unaware that their messages can be cracked, each sender tends to use the same book passage over and over; all that changes is where in that passage they start the encryption. Being very lazy, they always start the encryption within 20 letters of the start of the passage. So for the purposes of this task, the 'key' is simply the starting position in the book text, and is a number from 0 to 20. Your job now is to write a computer program (a real executable program, not a spreadsheet) that can be used to decrypt these intercepted messages. The program will be required to read the ciphertext from a file and to display the plaintext on the screen, along with the key that was used to encrypt it. You will be asked to demonstrate your program to the tutor in the lab class on the due date. This is so that you will be there to run the program and make any decisions that need making. You will be given several ciphertexts to practice on, but in the demonstration you will be asked to demonstrate your program on files you have not seen. You may write your program in whatever programming language you wish.


Related Discussions:- Write a program to decrypt encrypted messages

Explain the comma operator- computer programming, Explain the Comma Operato...

Explain the Comma Operator- Computer Programming? The comma has two utilization and the most common use is as a parameter separator for data types and function parameter lists. H

Pseudo code, I need help putting this into a flowchart constant c as Intege...

I need help putting this into a flowchart constant c as Integer = 3500 Constant CALORIESTOOUNCE as Integer = 219 Declare Sex as Character Declare Age as Integer Declare Weight as I

Write an implementation for the prime machine, You should use the BToolkit ...

You should use the BToolkit to produce the answers to the questions below. Where applicable, please use the machine names and identifier names suggested in the question to help me

Cookies management with perl, One of the main strengths of the Perl program...

One of the main strengths of the Perl programming language are its powerful text manipulation features. In this assignment, you will put them to use for writing a Perl program that

Develop a windows forms application, Develop a Windows Forms Application by...

Develop a Windows Forms Application by creating a new project named "xxxxxxxx" in a new folder named "xxxxxxxxas3" where xxxxxxxx is your student id. You should delete file(s) with

Application for a mid , The assignment has two parts: first you generate a ...

The assignment has two parts: first you generate a simple application for a MID that operates independently of other MIDs. As a second part, the application is extended to keep so

Maximization, A company produces three sizes of window fans small, medium a...

A company produces three sizes of window fans small, medium and large. the manager has formulated an LP model for fan production Maximize 6x1+8x2+5x3

Javascript variables and datatypes, Let us first see the skeleton of a Java...

Let us first see the skeleton of a JavaScript file. JavaScript code should be written between the and tags. The value LANGUAGE = "JavaScript" indicates to the browser that J

Shell script to compare that given two files are same or not, Normal 0 ...

Normal 0 false false false EN-US X-NONE X-NONE MicrosoftInternetExplorer4

C++, Have the user input two values. Store them in variables called saving...

Have the user input two values. Store them in variables called savings and expenses, both of data type double. If expenses is less than savings, subtract expenses from savings, o

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