Funcion
Funcion para encriptar y desencriptar...imagenes de BACOSI, cuyo formato es jpg.


#include "stdio.h"
#include "stdlib.h"
#include "string.h"

//LLAVE PUBLICA
//"fnt_bacosi_datafile_malklin_b_c_a_n_i_16_08"

char Clave[] =
"fnt_bacosi_datafile_malklin_b_c_a_n_i_16_08";
char ArchivoOrigen[] =
"D:\\Fintec\\CGI\\Imagenes\\Frente.FNA";
char ArchivoDestino[] =
"D:\\Fintec\\CGI\\Imagenes\\Frente.jpg";

//ESTRUCTURA DEL ARCHIVO PARA LA ENCRIPTACION
unsigned long crc_32_tab[] =
{
0x00000000L, 0x77073096L, 0xee0e612cL,
0x990951baL, 0x076dc419L,
0x706af48fL, 0xe963a535L, 0x9e6495a3L,
0x0edb8832L, 0x79dcb8a4L,
0xe0d5e91eL, 0x97d2d988L, 0x09b64c2bL,
0x7eb17cbdL, 0xe7b82d07L,
0x90bf1d91L, 0x1db71064L, 0x6ab020f2L,
0xf3b97148L, 0x84be41deL,
0x1adad47dL, 0x6ddde4ebL, 0xf4d4b551L,
0x83d385c7L, 0x136c9856L,
0x646ba8c0L, 0xfd62f97aL, 0x8a65c9ecL,
0x14015c4fL, 0x63066cd9L,
0xfa0f3d63L, 0x8d080df5L, 0x3b6e20c8L,
0x4c69105eL, 0xd56041e4L,
0xa2677172L, 0x3c03e4d1L, 0x4b04d447L,
0xd20d85fdL, 0xa50ab56bL,
0x35b5a8faL, 0x42b2986cL, 0xdbbbc9d6L,
0xacbcf940L, 0x32d86ce3L,
0x45df5c75L, 0xdcd60dcfL, 0xabd13d59L,
0x26d930acL, 0x51de003aL,
0xc8d75180L, 0xbfd06116L, 0x21b4f4b5L,
0x56b3c423L, 0xcfba9599L,
0xb8bda50fL, 0x2802b89eL, 0x5f058808L,
0xc60cd9b2L, 0xb10be924L,
0x2f6f7c87L, 0x58684c11L, 0xc1611dabL,
0xb6662d3dL, 0x76dc4190L,
0x01db7106L, 0x98d220bcL, 0xefd5102aL,
0x71b18589L, 0x06b6b51fL,
0x9fbfe4a5L, 0xe8b8d433L, 0x7807c9a2L,
0x0f00f934L, 0x9609a88eL,
0xe10e9818L, 0x7f6a0dbbL, 0x086d3d2dL,
0x91646c97L, 0xe6635c01L,
0x6b6b51f4L, 0x1c6c6162L, 0x856530d8L,
0xf262004eL, 0x6c0695edL,
0x1b01a57bL, 0x8208f4c1L, 0xf50fc457L,
0x65b0d9c6L, 0x12b7e950L,
0x8bbeb8eaL, 0xfcb9887cL, 0x62dd1ddfL,
0x15da2d49L, 0x8cd37cf3L,
0xfbd44c65L, 0x4db26158L, 0x3ab551ceL,
0xa3bc0074L, 0xd4bb30e2L,
0x4adfa541L, 0x3dd895d7L, 0xa4d1c46dL,
0xd3d6f4fbL, 0x4369e96aL,
0x346ed9fcL, 0xad678846L, 0xda60b8d0L,
0x44042d73L, 0x33031de5L,
0xaa0a4c5fL, 0xdd0d7cc9L, 0x5005713cL,
0x270241aaL, 0xbe0b1010L,
0xc90c2086L, 0x5768b525L, 0x206f85b3L,
0xb966d409L, 0xce61e49fL,
0x5edef90eL, 0x29d9c998L, 0xb0d09822L,
0xc7d7a8b4L, 0x59b33d17L,
0x2eb40d81L, 0xb7bd5c3bL, 0xc0ba6cadL,
0xedb88320L, 0x9abfb3b6L,
0x03b6e20cL, 0x74b1d29aL, 0xead54739L,
0x9dd277afL, 0x04db2615L,
0x73dc1683L, 0xe3630b12L, 0x94643b84L,
0x0d6d6a3eL, 0x7a6a5aa8L,
0xe40ecf0bL, 0x9309ff9dL, 0x0a00ae27L,
0x7d079eb1L, 0xf00f9344L,
0x8708a3d2L, 0x1e01f268L, 0x6906c2feL,
0xf762575dL, 0x806567cbL,
0x196c3671L, 0x6e6b06e7L, 0xfed41b76L,
0x89d32be0L, 0x10da7a5aL,
0x67dd4accL, 0xf9b9df6fL, 0x8ebeeff9L,
0x17b7be43L, 0x60b08ed5L,
0xd6d6a3e8L, 0xa1d1937eL, 0x38d8c2c4L,
0x4fdff252L, 0xd1bb67f1L,
0xa6bc5767L, 0x3fb506ddL, 0x48b2364bL,
0xd80d2bdaL, 0xaf0a1b4cL,
0x36034af6L, 0x41047a60L, 0xdf60efc3L,
0xa867df55L, 0x316e8eefL,
0x4669be79L, 0xcb61b38cL, 0xbc66831aL,
0x256fd2a0L, 0x5268e236L,
0xcc0c7795L, 0xbb0b4703L, 0x220216b9L,
0x5505262fL, 0xc5ba3bbeL,
0xb2bd0b28L, 0x2bb45a92L, 0x5cb36a04L,
0xc2d7ffa7L, 0xb5d0cf31L,
0x2cd99e8bL, 0x5bdeae1dL, 0x9b64c2b0L,
0xec63f226L, 0x756aa39cL,
0x026d930aL, 0x9c0906a9L, 0xeb0e363fL,
0x72076785L, 0x05005713L,
0x95bf4a82L, 0xe2b87a14L, 0x7bb12baeL,
0x0cb61b38L, 0x92d28e9bL,
0xe5d5be0dL, 0x7cdcefb7L, 0x0bdbdf21L,
0x86d3d2d4L, 0xf1d4e242L,
0x68ddb3f8L, 0x1fda836eL, 0x81be16cdL,
0xf6b9265bL, 0x6fb077e1L,
0x18b74777L, 0x88085ae6L, 0xff0f6a70L,
0x66063bcaL, 0x11010b5cL,
0x8f659effL, 0xf862ae69L, 0x616bffd3L,
0x166ccf45L, 0xa00ae278L,
0xd70dd2eeL, 0x4e048354L, 0x3903b3c2L,
0xa7672661L, 0xd06016f7L,
0x4969474dL, 0x3e6e77dbL, 0xaed16a4aL,
0xd9d65adcL, 0x40df0b66L,
0x37d83bf0L, 0xa9bcae53L, 0xdebb9ec5L,
0x47b2cf7fL, 0x30b5ffe9L,
0xbdbdf21cL, 0xcabac28aL, 0x53b39330L,
0x24b4a3a6L, 0xbad03605L,
0xcdd70693L, 0x54de5729L, 0x23d967bfL,
0xb3667a2eL, 0xc4614ab8L,
0x5d681b02L, 0x2a6f2b94L, 0xb40bbe37L,
0xc30c8ea1L, 0x5a05df1bL,
0x2d02ef8dL
};

static unsigned short key3;
static unsigned long key0,key1,key2;
static char contrasena[120];
static char *indice;
static int bite;
static unsigned short tem;

unsigned long crc32(unsigned long valor, int car);
int CLAVE(char contrasena[120]);
int DESCODIFICAR(char a);
int CODIFICAR(char a);
int encriptar(int nmTipo, char *szClave, char
*szFileDestino, char *szFileOrigen);

// -------Funciones --------
int encriptar(int nmTipo, char *szClave, char
*szFileDestino, char *szFileOrigen)
{
char c;
int en;

FILE *fdes,*fcod;

if ((fcod=fopen(szFileOrigen,"rb"))==NULL)
{
//"No se ha podido abrir el fichero a
codificar"
return 2;
}

if ((fdes=fopen(szFileDestino,"wb"))==NULL)
{
//"No se ha podido abrir el fichero resultado"
return 3;
}

if (szClave==NULL)
{
//"No se paso el argumento de la clave
return 4;
}

CLAVE(szClave);

c=getc(fcod);

while(!feof(fcod))
{
if (nmTipo == 1)
en=DESCODIFICAR(c);
else
en=CODIFICAR(c);

putc(en,fdes);
c=getc(fcod);
}

fclose(fdes);
fclose(fcod);

return 1;
}

unsigned long crc32(unsigned long valor, int car)
{
unsigned long i;

i=((valor)>>8)^(crc_32_tab[((int) (valor)^(car)) &
0xff]);
return i;
}

int CLAVE(char contrasena[120])
{
key0=305419896L;
key1=591751049L;
key2=878082192L;
indice=&contrasena[0];
while (*indice != '\0')
{
bite=(int) *(indice++);
key0=crc32(key0,bite);
key1+=key0 & 0xff;
key1=key1*134775813L+1;
key2=crc32(key2,(int)(key1 >> 24));
tem=(unsigned short) key2 | 2;
key3=((int) (((unsigned short) (tem*(tem^1)) >> 8)
& 0xff));
}
return 1;
}


int CODIFICAR(char a)
{
int retorna;

bite=((int) (a));
retorna=(bite^key3);
key0=crc32(key0,bite);
key1+=key0 & 0xff;
key1=key1*134775813L+1;
key2=crc32(key2,(int)(key1 >> 24));
tem=(unsigned short) key2 | 2;
key3=((int) (((unsigned short) (tem*(tem^1)) >> 8)
& 0xff));

return retorna;
}

int DESCODIFICAR(char a)
{
int retorna;

bite=((int) (a));
retorna=(bite^key3);
key0=crc32(key0,retorna);
key1+=key0 & 0xff;
key1=key1*134775813L+1;
key2=crc32(key2,(int)(key1 >> 24));
tem=(unsigned short) key2 | 2;
key3=((int) (((unsigned short) (tem*(tem^1)) >> 8)
& 0xff));
return retorna;
}
//---------------------------------------------------------------------------

int main(int argc, char* argv[])
{
encriptar(0, Clave, ArchivoDestino,
ArchivoOrigen);
return 0;
}
//---------------------------------------------------------------------------