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/*
* Copyright (C) 1998,1999,2000,2001,2002 Nikos Mavroyanopoulos
*
* This library is free software; you can redistribute it and/or modify it
* under the terms of the GNU Library General Public License as published
* by the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Library General Public License for more details.
*
* You should have received a copy of the GNU Library General Public
* License along with this library; if not, write to the
* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
* Boston, MA 02111-1307, USA.
*/
#include <libdefs.h>
#include <mcrypt_modules.h>
#define _init_mcrypt ofb_LTX__init_mcrypt
#define _mcrypt_set_state ofb_LTX__mcrypt_set_state
#define _mcrypt_get_state ofb_LTX__mcrypt_get_state
#define _end_mcrypt ofb_LTX__end_mcrypt
#define _mcrypt ofb_LTX__mcrypt
#define _mdecrypt ofb_LTX__mdecrypt
#define _has_iv ofb_LTX__has_iv
#define _is_block_mode ofb_LTX__is_block_mode
#define _is_block_algorithm_mode ofb_LTX__is_block_algorithm_mode
#define _mcrypt_get_modes_name ofb_LTX__mcrypt_get_modes_name
#define _mcrypt_mode_get_size ofb_LTX__mcrypt_mode_get_size
#define _mcrypt_mode_version ofb_LTX__mcrypt_mode_version
typedef struct ofb_buf {
byte* s_register;
byte* enc_s_register;
int blocksize;
} OFB_BUFFER;
/* OFB MODE */
int _init_mcrypt( OFB_BUFFER* buf, void *key, int lenofkey, void *IV, int size)
{
buf->s_register = buf->enc_s_register = NULL;
buf->blocksize = size;
/* For ofb */
buf->s_register=malloc( size);
if (buf->s_register==NULL) goto freeall;
buf->enc_s_register=malloc( size);
if (buf->enc_s_register==NULL) goto freeall;
if (IV!=NULL) {
memcpy(buf->s_register, IV, size);
} else {
memset(buf->s_register, 0, size);
}
/* End ofb */
return 0;
freeall:
free(buf->s_register);
free(buf->enc_s_register);
return -1;
}
int _mcrypt_get_state( OFB_BUFFER* buf, byte *IV, int *size)
{
if (*size < buf->blocksize) {
*size = buf->blocksize;
return -1;
}
*size = buf->blocksize;
memcpy( IV, buf->s_register, buf->blocksize);
return 0;
}
int _mcrypt_set_state( OFB_BUFFER* buf, void *IV, int size)
{
memcpy(buf->enc_s_register, IV, size);
memcpy(buf->s_register, IV, size);
return 0;
}
void _end_mcrypt( OFB_BUFFER* buf) {
free(buf->s_register);
free(buf->enc_s_register);
}
int _mcrypt( OFB_BUFFER* buf,void *plaintext, int len, int blocksize, void* akey, void (*func)(void*,void*), void (*func2)(void*,void*) )
{ /* plaintext is 1 byte (8bit ofb) */
char *plain = plaintext;
int i, j;
void (*_mcrypt_block_encrypt) (void *, void *);
_mcrypt_block_encrypt = func;
for (j = 0; j < len; j++) {
memcpy(buf->enc_s_register, buf->s_register, blocksize);
_mcrypt_block_encrypt(akey, buf->enc_s_register);
plain[j] ^= buf->enc_s_register[0];
/* Shift the register */
for (i = 0; i < (blocksize - 1); i++)
buf->s_register[i] = buf->s_register[i + 1];
buf->s_register[blocksize - 1] = buf->enc_s_register[0];
}
return 0;
}
int _mdecrypt( OFB_BUFFER* buf, void *plaintext, int len, int blocksize, void* akey, void (*func)(void*,void*), void (*func2)(void*,void*))
{ /* plaintext is 1 byte (8bit ofb) */
char *plain = plaintext;
int i, j;
void (*_mcrypt_block_encrypt) (void *, void *);
_mcrypt_block_encrypt = func;
for (j = 0; j < len; j++) {
memcpy(buf->enc_s_register, buf->s_register, blocksize);
_mcrypt_block_encrypt(akey, buf->enc_s_register);
/* Shift the register */
for (i = 0; i < (blocksize - 1); i++)
buf->s_register[i] = buf->s_register[i + 1];
buf->s_register[blocksize - 1] = buf->enc_s_register[0];
plain[j] ^= buf->enc_s_register[0];
}
return 0;
}
int _is_block_mode() { return 0; }
int _has_iv() { return 1; }
int _is_block_algorithm_mode() { return 1; }
char *_mcrypt_get_modes_name() { return "OFB"; }
int _mcrypt_mode_get_size () {return sizeof(OFB_BUFFER);}
word32 _mcrypt_mode_version() {
return 20010310;
}
#ifdef WIN32
# ifdef USE_LTDL
WIN32DLL_DEFINE int main (void)
{
/* empty main function to avoid linker error (see cygwin FAQ) */
}
# endif
#endif
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