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Simple encyption

 

Simple encyption
j_wolfe

9 Jan, 2009 - 10:34 AM
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Hello, I am trying to make a simple c++ program that encrypts text given by the user, using a password also given by the user. I apologize for any blatant misuse of the language, as I have not had formal training. My code just outputs the password and a funny looking question mark, rather than encrypting.
CODE

#include <iostream>
#include <sstream>

using namespace std;
//to be encrypted
string textin = "";
//password
string pass = "";
int main()
{
//gather text to be encrypted and password
cout<<"Enter the text to be encrypted:\n";
cin>>textin;
cout<<"Enter the password used to encrypt the text:\n";
cin>>pass;
//try to encrypt
for(int i = 0; i < textin.size(); i++)
    {
    textin[i]=textin[i]+pass[i];
        //fail at adding strings
    }
cout<<textin;
return 0;
}

I know that adding strings is wrong, but I'm not sure what I should be doing instead. It works fine incrementing the text by a set value, but this code fails. Anything you can do, or material you can point me to is greatly appreciated. Thanks.

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kapax

RE: Simple Encyption

9 Jan, 2009 - 11:04 AM
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Try this (i added one loop and changed a line inside your loop) and tell if you are satisfied:

CODE

#include <iostream>
#include <sstream>

using namespace std;
//to be encrypted
string textin = "";
//password
string pass = "";
int main()
{
//gather text to be encrypted and password
cout<<"Enter the text to be encrypted:\n";
cin>>textin;
cout<<"Enter the password used to encrypt the text:\n";
cin>>pass;
//try to encrypt

string modifiedPass = "";
modifiedPass.append(pass);
for (int j = 0; j < textin.size(); j++) {
    if (j % pass.length() == 0 || j+1 == textin.length())
        modifiedPass.append(pass);
}

for(int i = 0; i < textin.size(); i++)
    {
    textin[i]=textin[i]+modifiedPass[i];
        //fail at adding strings
    }
cout<<textin;
return 0;
}



Basically, what I did, is creating a new string and making it the length of the input text.
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matthew180

RE: Simple Encyption

9 Jan, 2009 - 12:17 PM
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I hope you are using this code only for academic purposes (your encryption is very weak). If this is going to be anything real-world, to protect anything of value (an account, personal information, etc.) then please consider using mcrypt.

Matthew
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Hyper

RE: Simple Encyption

9 Jan, 2009 - 12:56 PM
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You could use Windows 98's method of password encryption: XOR the input! biggrin.gif

EDIT: Because I hate people who never provide at least tiny examples, here:
variable ^= number

This post has been edited by Hyper: 9 Jan, 2009 - 12:57 PM
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j_wolfe

RE: Simple Encyption

9 Jan, 2009 - 01:36 PM
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Thank you, kapax, that seems to work. The terminal doesn't seem to like the characters output, but my intent was to save it to a file anyway.

In response to Matthew, this is not for practical use. I just thought it might be kind of fun, that's all. I wasn't aware that such a library existed, but I think by doing it myself I learn more.

That is an interesting concept, Hyper, though I'm not entirely sure how that would work (programming, as you can probably tell, is not yet something I'm good at)
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KYA

RE: Simple Encyption

9 Jan, 2009 - 01:58 PM
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#include <nerd.h>
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Mathematical idea, doing something then undoing it yields the same/original item.
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Hyper

RE: Simple Encyption

9 Jan, 2009 - 11:08 PM
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QUOTE(j_wolfe @ 9 Jan, 2009 - 01:36 PM) *
That is an interesting concept, Hyper, though I'm not entirely sure how that would work (programming, as you can probably tell, is not yet something I'm good at)


It would work something like this (psuedo code):
User enters string of characters into a C-style string: char UserInput[50]
After the user is done entering their string, you do the following:
for (int x = 0; x < 50; x++) { UserInput[x] ^= 50; }

That would cause each letter to be XOR'd with the value of 50. Here's a Wikipedia link to what XOR is:
I lied, it isn't Wikipedia

Welcome! I hope you understand you can simply output the encrypted string to a file once complete.
If this post was helpful, remember to click the green button that says: This Post Was Helpful! to save a kid in China (somehow...)!

This post has been edited by Hyper: 9 Jan, 2009 - 11:08 PM
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j_wolfe

RE: Simple Encyption

10 Jan, 2009 - 08:41 AM
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I see now. I just didn't get what you would be XORing.
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Hyper

RE: Simple Encyption

10 Jan, 2009 - 09:57 AM
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QUOTE(j_wolfe @ 9 Jan, 2009 - 10:34 AM) *

Hello, I am trying to make a simple c++ program that encrypts text given by the user, using a password also given by the user. I apologize for any blatant misuse of the language, as I have not had formal training. My code just outputs the password and a funny looking question mark, rather than encrypting.
[code]


I'm just curious, did you ever pass the first grade?
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j_wolfe

RE: Simple Encyption

10 Jan, 2009 - 10:12 AM
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I'm sorry that I couldn't take "XOR the input" and extrapolate "XOR the values of the input text and the password". When you said "input", I thought you meant the text to be encrypted. Perhaps if you had said 'inputs', but I'm not sure that would have been proper english.

Maybe things were different when you were in first grade, but I don't remember talking about bitwise operations or encryption techniques.

This post has been edited by j_wolfe: 10 Jan, 2009 - 10:16 AM
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Hyper

RE: Simple Encyption

10 Jan, 2009 - 10:51 AM
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OK. I'll dumb myself down that far then. Here you go idiot:
ENCRYPTION
#include <iostream>
using namespace std;

int main() {

    char INPUT[15] = {'\0'};

    printf("Enter 14 keys: ");
    cin.getline(INPUT, 14, '\n');

    for (int x = 0; x < strlen(INPUT); x++) { INPUT[x] ^= 15; }

    printf("Encrypted message: %s", INPUT);
    _flushall();

    cin.get();
    return 0;
}


Fucking welcome.
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