tomcrypt/rsa_v15_encrypt_key.c
2010-06-16 12:38:20 +02:00

55 lines
1.5 KiB
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"
#ifdef MRSA
/* PKCS #1 v1.5 pad then encrypt */
int rsa_v15_encrypt_key(const unsigned char *inkey, unsigned long inlen,
unsigned char *outkey, unsigned long *outlen,
prng_state *prng, int prng_idx,
rsa_key *key)
{
unsigned long modulus_bitlen, modulus_bytelen, x;
int err;
_ARGCHK(inkey != NULL);
_ARGCHK(outkey != NULL);
_ARGCHK(outlen != NULL);
_ARGCHK(key != NULL);
/* valid prng? */
if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
return err;
}
/* get modulus len in bits */
modulus_bitlen = mp_count_bits(&(key->N));
/* outlen must be at least the size of the modulus */
modulus_bytelen = mp_unsigned_bin_size(&(key->N));
if (modulus_bytelen > *outlen) {
return CRYPT_BUFFER_OVERFLOW;
}
/* pad it */
x = *outlen;
if ((err = pkcs_1_v15_es_encode(inkey, inlen, modulus_bitlen, prng, prng_idx, outkey, &x)) != CRYPT_OK) {
return err;
}
/* encrypt it */
return rsa_exptmod(outkey, x, outkey, outlen, PK_PUBLIC, prng, prng_idx, key);
}
#endif