Thread: Cipher File

ı want to make a file which is cipher file.. my algorithm is

open current file
create new file
while EOF
(
read byte from current file (int form)
byte XOR 1
write new byte to new file
)

close
close etc...
is it possible?? if its possible how can ı do this.. give advice....

koyboy,

I recommend that you "develop" your code one step at a time... This is a good approach to any programming task...

1. Start with a program that reads one byte at a time and displays it. I'd suggest displaying the numerical value and the ASCII character (if any) for each byte. (It's always helpful to "see" what your program is doing.)

2. Add the code to save each byte to a new file. (If you read/write a simple text file, you can check your new file with Notepad (or a similar text editor) to make sure everything's working properly so far.

3. Add the code to encrypt each byte before saving it. (It would probably be helpful to display the encrypted byte along with the unencrypted byte.)

4. When everything works, you can delete (or comment-out) the code that displays the bytes.

thanks for your interest.. ı wrote it like this..

Code:

FILE *in,*out;
in  = fopen(gonder,  "rb");
    out = fopen(yeni, "wb");
    while((ch = fgetc(in)) != EOF)
        putc(ch ^ 1, out);    
    fclose(out);
    fclose(in);

Great start! You could also try something like some sort of simple password key.

Example:

Code:

#include <cstdlib>
#include <cstdio>
#include <cstring>

#define BUF_SIZE  256

int main(void)
{
    char buffer[BUF_SIZE];

    std::puts("Password: ");
    std::fgets(buffer, BUF_SIZE, stdin);

    std::FILE *in, *out;

    in = std::fopen("gonder", "rb");
    out = std::fopen("yeni", "wb");

    if(in && out)
    {
        int size = std::strlen(buffer), i = 0, ch;

        while(!std::feof(in))
        {
            if((ch = std::fgetc(in)) != EOF)
                std::putc(ch ^ buffer[i % size], out);
            ++i;
        }

        std::fclose(in);
        std::fclose(out);

        return 0;
    }

    if(in)
       std::fclose(in);
    if(out)
       std::fclose(out);

    return -1;
}

Just to maybe give you a nudge in the direction you are wishing to go.

is this for an assignment or do you just need some encryption/decryption code?