bigpoint_crypt.c
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#include <stdarg.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <mcrypt.h>
#include <mhash.h>
#include "bigpoint_crypt.h"
static
void
__construct(struct BIGPOINT_CRYPT * _this, va_list * params)
{
_this->algorithm = va_arg(* params, const char * const);
_this->mode = va_arg(* params, const char * const);
_this->mcrypt = mcrypt_module_open(
(char *)_this->algorithm,
NULL,
(char *)_this->mode,
NULL);
_this->ivsize = mcrypt_enc_get_iv_size(_this->mcrypt);
_this->keysize = mcrypt_enc_get_key_size(_this->mcrypt);
}
static
void
__destruct(struct BIGPOINT_CRYPT * _this)
{
if (_this->iv) {
free(_this->iv);
}
mcrypt_module_close(_this->mcrypt);
}
static const
struct BIGPOINT_CCLASS _bigpoint_crypt = {
sizeof(struct BIGPOINT_CRYPT),
(ctor)__construct,
NULL,
(dtor)__destruct,
NULL
};
const struct BIGPOINT_CCLASS * const BIGPOINT_CRYPT = &_bigpoint_crypt;
static
void
mcrypt_close(MCRYPT * mcrypt)
{
mcrypt_free(*mcrypt);
*mcrypt = NULL;
}
void *
bigpoint_crypt_createIv(struct BIGPOINT_CRYPT * _this)
{
int urandom;
size_t rsize = 0;
void * iv = NULL;
iv = calloc(_this->ivsize, sizeof(char));
urandom = open("/dev/urandom", O_RDONLY);
rsize = read(urandom, iv, _this->ivsize);
if (_this->ivsize != rsize) {
free(iv);
iv = NULL;
}
return iv;
}
static
void *
createKey(struct BIGPOINT_CRYPT * _this, const char * const password)
{
void * key = NULL;
key = calloc(_this->keysize, sizeof(char));
mhash_keygen(
KEYGEN_MCRYPT,
MHASH_SHA256,
mhash_keygen_count(),
key,
_this->keysize,
NULL,
0,
(char *)password, // @TODO: bad karma...now this might change password.
strlen(password));
return key;
}
void *
bigpoint_crypt_encrypt(
struct BIGPOINT_CRYPT * _this,
const void * const data,
const char * const password,
size_t * length)
{
char * encrypted;
void * iv;
void * key;
key = createKey(_this, password);
if(_this->iv) {
iv = _this->iv;
} else {
iv = bigpoint_crypt_createIv(_this);
}
mcrypt_generic_init(_this->mcrypt, key, _this->keysize, iv);
encrypted = calloc(_this->ivsize + *length, sizeof(char));
memcpy(encrypted, iv, _this->ivsize);
memcpy(encrypted + _this->ivsize, data, *length);
mcrypt_generic(_this->mcrypt, encrypted + _this->ivsize, *length);
mcrypt_generic_deinit(_this->mcrypt);
*length += _this->ivsize;
free(key);
if (_this->iv != iv) {
free(iv);
}
return encrypted;
}
void *
bigpoint_crypt_decrypt(
struct BIGPOINT_CRYPT * _this,
const void * const data,
const char * const password,
size_t * length)
{
char * decrypted;
void * iv;
void * key;
key = createKey(_this, password);
iv = calloc(_this->ivsize, sizeof(char));
memcpy(iv, data, _this->ivsize);
mcrypt_generic_init(_this->mcrypt, key, _this->keysize, iv);
*length -= _this->ivsize;
decrypted = calloc(*length, sizeof(char));
memcpy(decrypted, data + _this->ivsize, *length);
mdecrypt_generic(_this->mcrypt, decrypted, *length);
mcrypt_generic_deinit(_this->mcrypt);
free(key);
free(iv);
return decrypted;
}
// vim: set et ts=4 sw=4: