Hello Everyone.
i have created a XOR Encryption libary in c...well tried with some help. But there is something wrong with my coding as when i try and decrypt a file, it doesnt always decrypt as plain text as some charfacters seem malformed. Please could you help me fix this problem and possibly update this to c++, thanks alot people, you rock.
Requests...
Fix the main problem below
Fix mistakes in the code
Make necessary improvements to the code
Revise code and update to C++ if possibleProblem...
Original File
[B][I]This is a test of the encryption libary.[/I][/B]
Encrypted File
[B][I]'ᜈṏ䌀倀攑琖漠漛ฤ牣灹楴湯氠扩牡[/I][/B]
Decrypted File
[B][I]This is a test oAÀòXe encryp`Æ<ldÃø`ary.[/I][/B]The Functions...
crypt - This will crypt a given file with a given seed string.
cryptf - Similar to crypt, only you provide a seed File instead of a seed string.
crypto - This will crypt a given file with a given seed string.
cryptof - This will crypt a given file with a given seed fileThe Source Code...
#define export __declspec (dllexport)
#include <stdio.h>
long filesize(FILE *f)
{
long fs;
fseek(f,0L,SEEK_END);
fs = ftell(f);
fseek(f,0L,SEEK_SET);
return fs;
}
export double crypt(char *rn, char *wn, char *sb, double ss)
{
FILE *rf, *wf;
unsigned char fb[BUFSIZ];
unsigned int bp, sp = 0;
size_t bs;
if ((rf = fopen(rn,"rb")) == NULL) { return 0; }
if ((wf = fopen(wn,"wb")) == NULL) { return 0; }
while ((bs = fread(fb, 1, BUFSIZ, rf)) != 0)
{
for ( bp = 0; bp < bs; ++bp )
{
fb[bp] ^= sb[sp++];
if ( sp == ss )
{
sp = 0;
}
}
fwrite(fb, 1, bs, wf);
}
fclose(wf);
fclose(rf);
return 1;
}
export double cryptf(char *fn, char *tn, char *sn)
{
FILE *f;
unsigned char *sb;
double ss;
if ((f = fopen(sn,"rb")) == NULL) { return 0; }
ss = filesize(f);
if ((sb = (char *) malloc(sizeof(char) * ss)) == NULL) { return 0; }
fread(sb,ss,1,f);
fclose(f);
double r = crypt(fn,tn,sb,ss);
free(sb);
return r;
}
export double crypto(char *fn, char *sb, double ss)
{
FILE *f;
unsigned char fb[BUFSIZ];
unsigned int bp, sp = 0;
long rp, wp;
size_t bs;
if ((f = fopen(fn,"rb+")) == NULL)
{
return 0;
}
rp = wp = ftell(f);
while ((bs = fread(fb, 1, BUFSIZ, f)) != 0)
{
rp = ftell(f);
for ( bp = 0; bp < bs; ++bp )
{
fb[bp] ^= sb[sp++];
if ( sp == ss )
{
sp = 0;
}
}
fseek(f,wp,SEEK_SET);
fwrite(fb, 1, bs, f);
fflush(f);
wp = ftell(f);
fseek(f,rp,SEEK_SET);
}
fclose(f);
return 1;
}
export double cryptof(char *fn, char *sn)
{
FILE *f;
char *sb;
double ss;
if ((f = fopen(sn,"rb")) == NULL) { return 0; }
ss = filesize(f);
if ((sb = (char *) malloc(sizeof(char) * ss)) == NULL) { return 0; }
fread(sb,ss,1,f);
fclose(f);
double r = crypto(fn,sb,ss);
free(sb);
return r;
}Kind Regards,
Nathaniel Blackburn
