tomcrypt/rsa_encrypt_key.c
2010-06-16 12:38:13 +02:00

60 lines
1.7 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
/* OAEP pad then encrypt */
int rsa_encrypt_key(const unsigned char *inkey, unsigned long inlen,
unsigned char *outkey, unsigned long *outlen,
const unsigned char *lparam, unsigned long lparamlen,
prng_state *prng, int prng_idx, int hash_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 and hash ? */
if ((err = prng_is_valid(prng_idx)) != CRYPT_OK) {
return err;
}
if ((err = hash_is_valid(hash_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;
}
/* OAEP pad the key */
x = *outlen;
if ((err = pkcs_1_oaep_encode(inkey, inlen, lparam,
lparamlen, modulus_bitlen, prng, prng_idx, hash_idx,
outkey, &x)) != CRYPT_OK) {
return err;
}
/* rsa exptmod the OAEP pad */
return rsa_exptmod(outkey, x, outkey, outlen, PK_PUBLIC, prng, prng_idx, key);
}
#endif /* MRSA */