CSCI 344: Intro To Computer Communications

Program 2: Slightly Modified Beale Code Encipherer/Decipherer (MBC)

Goal:

• Write two programs.
  • Client Program - Acts as the user interface
  • Server Program - Takes commands, does requested work and returns results to a client program.
• All communications between the client and server must be done using UNIX C++ Sockets.
• Use loopback for server host

Client Program:

• Commands:
  • 'e' or 'E'
    • Encipher command
    • Sends the data to server to be enciphered using the MBC encryption alg.
    • Server will encipher data and return the cipher code
    • Client then displays the original string followed by the cipher code on the line below
    • Should be neat and labeled.
    • Take input from command line
  • 'd' or 'D'
    • Oppose of encipher command
    • Take cipher code as input and send to server to decipher
    • When done, print both cipher code and deciphered code to screen neatly in client program
    • String on command line should be integers seperated by at least one blank
  • 'q' or 'Q'
    • Quit
    • Get out of loop and say bye to user

Server Program:

• Take a command from client until the command 'q' is read
• Encipher or Decipher based upon the command recieved ('e' or 'd')
• Data packet will never be longer than 80bytes
• Should have no screen output from server code with the exception of error messages (All I/O happens from within the client)

Notes:

• Must read command line all at once (Dont break up the command with another prompt)
• Clear the screen often
• Five files located on the CSCI 344 home page will help
  • BCipher.h - MBC class definition file
  • BCipher.cpp - MBC class implementation file
  • bcdriver.cpp - Example driver program to show how to call BCipher methods
  • bc2.txt - Cipher text for Beale Cipher 2, the solved one
  • DOI.txt - Modified version of US Declartion of Independence to work with program.
• Refer to http://en.wikipedia.org/wiki/Beale_ciphers