41 lines
934 B
C
41 lines
934 B
C
|
/* LibTomCrypt, modular cryptographic library -- Tom St Denis
|
||
|
|
*
|
||
|
|
* LibTomCrypt is a library that provides various cryptographic
|
||
|
|
* algorithms in a highly modular and flexible manner.
|
||
|
|
*
|
||
|
|
* The library is free for all purposes without any express
|
||
|
|
* guarantee it works.
|
||
|
|
*
|
||
|
|
* Tom St Denis, tomstdenis@iahu.ca, http://libtomcrypt.org
|
||
|
|
*/
|
||
|
|
#include "mycrypt.h"
|
||
|
|
|
||
|
|
/* Integer to Octet I2OSP -- Tom St Denis */
|
||
|
|
|
||
|
|
#ifdef PKCS_1
|
||
|
|
|
||
|
|
/* always stores the same # of bytes, pads with leading zero bytes
|
||
|
|
as required
|
||
|
|
*/
|
||
|
|
int pkcs_1_i2osp(mp_int *n, unsigned long modulus_len, unsigned char *out)
|
||
|
|
{
|
||
|
|
int err;
|
||
|
|
unsigned long size;
|
||
|
|
|
||
|
|
size = mp_unsigned_bin_size(n);
|
||
|
|
|
||
|
|
if (size > modulus_len) {
|
||
|
|
return CRYPT_BUFFER_OVERFLOW;
|
||
|
|
}
|
||
|
|
|
||
|
|
/* store it */
|
||
|
|
zeromem(out, modulus_len);
|
||
|
|
if ((err = mp_to_unsigned_bin(n, out+(modulus_len-size))) != MP_OKAY) {
|
||
|
|
return mpi_to_ltc_error(err);
|
||
|
|
}
|
||
|
|
return CRYPT_OK;
|
||
|
|
}
|
||
|
|
|
||
|
|
#endif /* PKCS_1 */
|
||
|
|
|