I don't get it? This Should work?!

[why06]

THIS POST NO LONGER APPLIES. READ THIS ONE

Okay I've got a program that encrypts text with a key:

#include <iostream>
#include <fstream>
using namespace std;
void XOREncrypt(char* key, char* plaintext);

int main()
{
    char plaintext[50];
    char key[50];
    
    for(;;)
    {
     cout<<"Plaintext file name: ";
     cin >> plaintext;
     cout<<"Encryption Key: ";
     cin >> key;
     XOREncrypt(key, plaintext);
    }
    return 1;
}

void XOREncrypt(char* key, char* plaintext)
{
                 fstream plainfile(plaintext, ios::in | ios::out | ios::binary);
                 if(!plainfile)
                 {
                                cout <<"Error opening plaintext.\n";
                                return;
                                }
                 fstream cipherfile("ciphertext.txt", ios::in | ios::out | ios::binary | ios::trunc);
                 if (!cipherfile)
                 {
                                 cout << "Error opening chiphertext.txt.\n";
                                 return;
                                 }     
                 int i = 0;
                 char ch;
                 while(plainfile)
                 {
                  plainfile.get(ch);
                  if(plainfile)
                  {
                        cipherfile.put(ch ^ key[i]);
                        i++;
                        if(!key[i]) i = 0;
                  }
                 }
                 cout<< "XOR Encryption finished. Check ciphertext.txt" << endl;
                 return;
}

Just a simple XOR routine.
The key is: "key"

So now I have the plain text, and the cipher text:

Hello my name is Shaun.

#
YYEE*K

Ok. So now it would make sense to me that XORing the plaintext with the ciphertext would reveal the key.
for instance:
0000 1111 - plain
^1111 0000 - cipher
1111 1111 - key

See what I mean? So I made this program to do just that:

#include <iostream>
#include <fstream>
using namespace std;
void XOREncrypt(char* ciphertext, char* plaintext);

int main()
{
    char plaintext[50];
    char ciphertext[50];
    
    for(;;)
    {
     cout<<"Plaintext file name: ";
     cin >> plaintext;
     cout<<"Ciphertext filename: ";
     cin >> ciphertext;
     XOREncrypt(ciphertext, plaintext);
    }
    return 1;
}

void XOREncrypt(char* ciphertext, char* plaintext)
{
                 fstream plainfile(plaintext, ios::in | ios::out | ios::binary);
                 if(!plainfile)
                 {
                                cout <<"Error opening plaintext.\n";
                                return;
                                }
                 fstream cipherfile(ciphertext, ios::in | ios::out | ios::binary);     
                 if (!cipherfile)
                 {
                                 cout << "Error opening chiphertext.\n";
                                 return;
                                 }           
                 fstream keyfile("key.txt", ios::in | ios::out | ios::binary | ios::trunc);
                 if(!keyfile)
                 {
                             cout << "Error opening key.txt\n";
                             return;
                             }
                 
                 int i = 0;
                 char ch1, ch2;
                 while(plainfile && cipherfile)
                 {
                  plainfile.get(ch1);
                  cipherfile.get(ch2);
                  if(plainfile && cipherfile)
                  {
                        keyfile.put(ch1 ^ ch2);
                  }
                 }
                 cout<< "XOR Encryption finished. Check ciphertext.txt" << endl;
                 return;
}

Simple as pie...

Except instead of getting the key. I get this mess!:

·›OlO xy'nkm< os<S1apn*

might I ask? Wtf?! my head is smitten by new mistress and perplexity is her name.

Hmmm.. I should have checked the encryptor after I edited it. It seems like every little thing I do to it messes up the code immensely.

The closest thing I have got to fixing it is this:

HEllo, my namE is Shaun..)

and it keeps throwing in random capitalization and shit... I don't get it o_O... Is it so much to ask for something to just work?

EDIT:
Using this scheme...

#include <iostream>
#include <fstream>
using namespace std;
void XOREncrypt(char* key, char* plaintext);

int main()
{
    char* plaintext = new char[50];
    char* key = new char[50];
    
    for(;;)
    {
     plaintext = new char[50];
     key = new char[50];
     cout<<"Plaintext file name: ";
     cin >> plaintext;
     cout<<"Encryption Key: ";
     cin >> key;
     XOREncrypt(key, plaintext);
    }
    return 1;
}

void XOREncrypt(char* key, char* plaintext)
{
                 fstream plainfile(plaintext, ios::in | ios::out | ios::binary);
                 if(!plainfile)
                 {
                                cout <<"Error opening plaintext.\n";
                                return;
                                }
                 fstream cipherfile("ciphertext.txt", ios::in | ios::out | ios::binary | ios::trunc);
                 if (!cipherfile)
                 {
                                 cout << "Error opening chiphertext.txt.\n";
                                 return;
                                 }     
                 int i = 0;
                 char ch;
                 while(plainfile)
                 {
                  plainfile.get(ch);
                  if(!plainfile)break;
                  if(ch)
                  {
                        cipherfile.put(ch ^ key[i]);
                        i++;
                        if(!key[i]) i = 0;
                  }
                 }
                 cout<< "XOR Encryption finished. Check ciphertext.txt" << endl;
                 return;
}

I almost fixed it....

but the E is still capitalized....

HEllo my name is Shaun.

Why is this so fkin complicated D: ArGGGHH! It's supposed to be easy!

[Obama]

Its been 2 hours. Just wait

[Hell_Demon]

What compiler are you using why?
My MSVC++ 2003 complains about 'while(plainfile)'

[why06]

What compiler are you using why?
My MSVC++ 2003 complains about 'while(plainfile)'

Yeh well Im making it too complicated. Here this one i simple enough that anyone can analyze it quickly:

#include <iostream>
using namespace std;

int main()
{
    char p,c,k;
    p = 'p';//plain
    c = 'c';//cipher
    k = 'k';//key
    cout<<p<<endl; //prints plain character to screen
    
    c = p^k;
    cout<<c<<endl; //prints cipher character to screen
    
    k = c^p;
    cout<<k<<endl; //prints key to screen
    
    //Time for strings... these are more error prone//
    char* pp = new char[50];
    char* cp = new char[50];
    char* kp = new char[50];
    strcpy(pp,"plaintext plaintext plaintext");
    strcpy(cp,"cipher");
    strcpy(kp, "key");
    cout<<pp<<endl;
    
    //XORs plaintext with key
    for(int i = 0; pp[i]; i++)
    {
        if(!*kp)kp = "key";
        cp[i] = pp[i] ^ *(kp++);
    }
    cout << cp <<endl; // prints ciphertext to screen
    
    //XORs plaintext with cipertext. This should reveal key
    char* t = new char[50];
    for(int i = 0; pp[i]; i++)
    {
         t[i] = pp[i] ^ cp[i];
    }
    cout<< t <<endl; //prints keytext to screen
    
    system("pause");
    
    return 1;
}

p
←
k
plaintext plaintext plaintext
K§§ ↑☻♂
♀↨▼
keykeykeykeykeykeykeykeykeykeSORS=2

See the key is revealed, but there are also some errors tacked on to the end.(SORS=2) Now it seems the longer the text gets the worse the errors. So I need to nip this out. I know I have played out this XOR thing, but it's important that I get it exactly right! If there are errors in my own algorithms, especially one this simple... how can I hope to crack others encryption?

[Matrix_NEO006]

u defined key as char and char is ' ' not " ". unless you convert it with sZ.
u need to convert char to string.
https://www.linuxquestions.org/questi...r-in-c-423771/

[why06]

u defined key as char and char is ' ' not " ". unless you convert it with sZ.
u need to convert char to string.

What line are you talking about? Can you show me?

[Matrix_NEO006]

What line are you talking about? Can you show me?

if(!*kp)kp = "key";

[why06]

if(!*kp)kp = "key";

kp is a char*

here is the declaration: char* kp = new char[50];

So I can do that.... =/

[Matrix_NEO006]

usually char should be like this
if(!*kp)kp = 'key';

[why06]

usually char should be like this
if(!*kp)kp = 'key';

lol it's not a char, it is a char*... You may be confused because I tested the value of kp rather then index it like usual e.g. (kp[i]) Also I incremented the pointer using (kp++)

[Obama]

-sigh, this shit is WAY over mah head.

[why06]

-sigh, this shit is WAY over mah head.

Lol. No worries bro. You were right about me giving up too soon. Hopefully BlackAngel or Jetamay will stop in. Not like Im in a rush. I have a million things to do before schools out and this isn't a high priority.

[crushed]

Lol. No worries bro. You were right about me giving up too soon. Hopefully BlackAngel or Jetamay will stop in. Not like Im in a rush. I have a million things to do before schools out and this isn't a high priority.

I hate you. LOL, made me come back to programming. After that, 'inspiring conversation' on MSN. LOL

Decided I'll do a bit of both, mix it up with Graphics, and Programming.

[Hell_Demon]

Uhm mister why, this works fine for me:

#include <windows.h>
#include <iostream>
#include <fstream>
using namespace std;
void XOREncrypt(int num, int key);

int main()
{
	int num=00001101;
	int key=10100000;
	while(1)
	{
        cout<<"Enter a number: ";
		cin >> num;
		if(num==9001)
		{
			break;
		}
		cout<<"Encryption Key: ";
		cin >> key;
		XOREncrypt(num, key);
	}
    return 1;
}

void XOREncrypt(int num, int key)
{
	cout<<"XOR Encryption finished. Here is the result: "<<(num ^ key) << endl;
}

Using numbers that works fine, try converting the char they enter to int first see if that works.

[why06]

Uhm mister why, this works fine for me:


Using numbers that works fine, try converting the char they enter to int first see if that works.

That might be the best way. Or just do it absolutely 1 char at a time. not using strings at all. I'll experiment around with some different techniques to see which is most error prone.