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

Write a complete program using floating-point operations, Question 1: a...

Question 1: a) Assume that B is an array of 50 words; write a code which will place the smallest integer of array B in register AX. b) Write a small code (only three instr

Java networking, Expertsmind brings you unique solution in java assignment...

Expertsmind brings you unique solution in java assignments Networking The term system selection represents composing applications that do across several gadgets (computers

Gridworld, how do I get my actor to spin

how do I get my actor to spin

econometrics using r, EF308 Assignment 2 Due: 3pm, 26 April 2012 Introduct...

EF308 Assignment 2 Due: 3pm, 26 April 2012 Introduction This assignment is loosely based on Cheung et al. (2005) and Molodtsova and Papell (2009) and examines the out-of- sample pr

Board coloring problem description, Board Coloring Problem Description ...

Board Coloring Problem Description In this problem you are given a board in which some of the elements are placed as shown in diagram below. Each element represents a color.

Unix, 1. Write a shell script to locate executable files. This script takes...

1. Write a shell script to locate executable files. This script takes a list of file names from the command line and determines which would be executed had these names been given a

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

Otrs customisation using perl, OTRS Customisation using Perl, MySQL Program...

OTRS Customisation using Perl, MySQL Programming OTRS is a perl based open source issue ticket management solution. Default performance features 'note-internal' that is visible

Matlab and Image Processing and Neural Network, I need to do image reconstr...

I need to do image reconstruction using Neural Network using Matlab

Create procedures for accessing the root, (a)  Create procedures for access...

(a)  Create procedures for accessing the root, left subtree and right subtree, and also mutators for changing the root, left subtree and right subtree of an avl argument. (b) Wr

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