Simple message encryption
I thought this would be a good read for any people new to C++. I have made a simple xor encryption program to encrypt simple oneline messages.
I kept it as simple as possible so people new to C++ might could learn something from it. Then again as my programming skills arent exectly "good" I might learn something myself after a few of you see it :D .
You simply give a file name a secret key and the message.
Code:
/******************************************************/
/* This program will encrypt and decrypt messages. The*/
/* user will simply have to remeber a secret key. */
/******************************************************/
#include <iostream>
#include <fstream>
#include <string>
using namespace std;
// Function Prototypes ---------------------------------
int GetUserChoice ();
void Encryption ();
void Decryption ();
string XorString ( string source, int key );
// -----------------------------------------------------
// Main Function ---------------------------------------
int main ()
{
// Variable to hold our choice
int choice;
// Create an infinite loop -------------------------
while ( 1 ) {
// GetUserChoice will return what the user wants to do
// We can assign the returned value to our variable
choice = GetUserChoice ();
// Now we can check what the user wants
if ( choice == 1 ) Encryption ();
else if ( choice == 2 ) Decryption ();
// If the choice was 3 that means we can break from our loop
else if ( choice == 3 ) break;
}
// -------------------------------------------------
return 0;
}
// GetUserChoice Function ------------------------------
int GetUserChoice ()
{
// Variable for the choice
int choice;
// Here we will print our menu and prompt for a number
// This number will represent what the user wants to do
// Once we have the number this function will return it
cout << "Message Encryption" << endl;
cout << "----------------------" << endl;
cout << "1) Encrypt Message" << endl;
cout << "2) Decrypt Message" << endl;
cout << "3) Exit" << endl << endl;
cout << "Make a selection: ";
cin >> choice;
// Now we will check to make sure the choice was valid
if ( choice != 1 && choice != 2 && choice != 3 ) {
cout << endl;
cout << "Please enter 1, 2, or 3" << endl;
cout << "Press enter to exit...";
// Since the user entered an invalid selection we
// will just exit the program by returning our programs
// exit code.. 3
cin.get ();
return 3;
}
// If it makes it to this point that means the input was valid so we can return it
return choice;
}
// -----------------------------------------------------
// Here is where we will encrypt the string ------------
string XorString ( string source, int key )
{
// Here we loop through each character, using binary xor on it.
for ( unsigned int loop = 0; loop < source.size (); loop ++ ) {
source [loop] ^= key;
}
return source;
}
// Here we will get the file name, key, and message from the user ----
void Encryption ()
{
// Variables for the file name, key and message ----
char file_name [255];
string message;
string encrypted_message;
int key;
// -------------------------------------------------
cout << endl;
cout << "Enter file name: ";
cin >> file_name;
cout << "Enter secret key: ";
cin >> key;
cout << "Enter your secret message." << endl;
cout << "Message: ";
// We need this to ignore anything that might be left over
// and ruin our message
cin.ignore ( 255, '\n' );
getline ( cin, message );
// Now we have all of the info we can encrypt and write --
// the string to the file --------------------------------
encrypted_message = XorString ( message, key );
ofstream file ( file_name );
file << encrypted_message;
file.close ();
// -------------------------------------------------------
cout << "Done..." << endl << endl;
}
// -------------------------------------------------------------------
// Decryption will work the same way. Instead of asking the user for the message, ---
// we print it out. -----------------------------------------------------------------
void Decryption ()
{
// Variables for the file name, key and message ----
char file_name [255];
string message;
int key;
// -------------------------------------------------
cout << endl;
cout << "Enter file name: ";
cin >> file_name;
cout << "Enter secret key: ";
cin >> key;
// Now we will check to see if the file exists -----
ifstream file ( file_name );
if ( !file.is_open () ) {
cout << "Failed to load " << file_name << "!" << endl;
cout << "Press enter to exit...";
cin.get ();
exit ( EXIT_FAILURE );
}
// -----------------------------------------------
getline ( file, message );
file.close ();
cout << "Message: " << XorString ( message, key ) << endl;
cout << "Done..." << endl << endl;
}
I am sure more experienced programmers will find several problems with my code :rolleyes:. But if you see any really big nono's be sure to point them out! This was a quick little boredom project I did to kill a good 30 mins. ENJOY!
EDIT:
Sorry for the indention errors. Seems the boards code tags doesnt like MinGW Studios formatted code :p
And I know its not extremely useful but hey you moght want to store a phone number or something :D
