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

We are need of a prestashop expert, We are need of a PrestaShop Expert W...

We are need of a PrestaShop Expert We are getting a fresh design created for our Jewellery website. This job is in 2 parts 1. The website engine is PrestaShop as well as w

Design a mobile web browser..., HOW CAN I DESIGN A MOBILE WEB BROWSER LIKE ...

HOW CAN I DESIGN A MOBILE WEB BROWSER LIKE OPERA MINI. USING VISUAL BASIC? HELP ME.

Matlab help, i(t)=(V/R) * (1-e^-(R/L)(t)) (a) Defi ne an anonymous function...

i(t)=(V/R) * (1-e^-(R/L)(t)) (a) Defi ne an anonymous function answerE that returns i(t) given input t. (b) The fi nal value for the current is 2 amps. Find a time tm when the curr

Statistical parametric mapping, A large offshore accommodation barge is to ...

A large offshore accommodation barge is to be converted into a floating luxury hotel.  It will be connected to a single point mooring buoy (SPM) in a beautiful inland loch where th

Shell script display time for user which is idle, Normal 0 fals...

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

Outline the norms to be designing a web page, Question: (a) Outline th...

Question: (a) Outline the six norms to be considered before designing a Web page. (b) Write a program such that when a user right-clicks anywhere on a Web page, the follow

Program for nuclear reactor - embedded systems, Implement the "Nuclear Reac...

Implement the "Nuclear Reactor" example using the following:  An ISR triggered by a button press  A task to update the temperatures  A semaphore to communicate between the ISR and

What is an authentication subsystem, Question: (i) All Security authen...

Question: (i) All Security authentication mechanism that run on the TRU64 Unix Operating system run under the Security Integration Architecture (SIA ) layer. Explain with di

Database, asample database report

asample database report

C language, write a program to find the output 1 ...

write a program to find the output 1 1 2 1 1 2 3 2 1 1 2 3 4 3 2 1 1 2 3 2 1 1 2 1 1

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