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Added define LTC_RSA_BLINDING to be able to disable rsa blinding

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This commit is contained in:
Steffen Jaeckel 2011-03-21 22:50:49 +01:00
parent 380693edd9
commit 8dc8a2d551
6 changed files with 75 additions and 24 deletions
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12
src/headers/tomcrypt_custom.h
View File

@ -289,10 +289,10 @@
#ifndef LTC_NO_MATH
/* LibTomMath */
/* #define LTM_LTC_DESC */
/* #define LTM_DESC */
/* TomsFastMath */
/* #define TFM_LTC_DESC */
/* #define TFM_DESC */
#endif /* LTC_NO_MATH */
@ -302,6 +302,9 @@
/* Include RSA support */
#define LTC_MRSA
/* Enable RSA blinding when doing private key operations? */
/* #define LTC_RSA_BLINDING */
/* Include Diffie-Hellman support */
#ifndef GPM_DESC
/* is_prime fails for GPM */
@ -382,6 +385,11 @@
#define LTC_PKCS_1
#endif
#if defined(TFM_DESC) && defined(LTC_RSA_BLINDING)
#warning RSA blinding currently not supported in combination with TFM
#undef LTC_RSA_BLINDING
#endif
#if defined(LTC_DER) && !defined(MPI)
#error ASN.1 DER requires MPI functionality
#endif

11
src/headers/tomcrypt_math.h
View File

@ -431,6 +431,15 @@ typedef struct {
@return CRYPT_OK on success
*/
int (*submod)(void *a, void *b, void *c, void *d);
/* ---- misc stuff ---- */
/** Make a pseudo-random mpi
@param a The mpi to make random
@param size The desired length
@return CRYPT_OK on success
*/
int (*rand)(void *a, int size);
} ltc_math_descriptor;
extern ltc_math_descriptor ltc_mp;
@ -515,6 +524,8 @@ extern const ltc_math_descriptor gmp_desc;
#define mp_tohex(a, b) mp_toradix(a, b, 16)
#define mp_rand(a, b) ltc_mp.rand(a, b)
#endif
/* $Source$ */

9
src/math/gmp_desc.c
View File

@ -409,6 +409,13 @@ static int isprime(void *a, int *b)
return CRYPT_OK;
}
static int set_rand(void *a, int size)
{
LTC_ARGCHK(a != NULL);
mpz_random(a, size);
return CRYPT_OK;
}
const ltc_math_descriptor gmp_desc = {
"GNU MP",
sizeof(mp_limb_t) * CHAR_BIT - GMP_NAIL_BITS,
@ -492,6 +499,8 @@ const ltc_math_descriptor gmp_desc = {
&addmod,
&submod,
&set_rand,
};

10
src/math/ltm_desc.c
View File

@ -408,7 +408,13 @@ static int isprime(void *a, int *b)
err = mpi_to_ltc_error(mp_prime_is_prime(a, 8, b));
*b = (*b == MP_YES) ? LTC_MP_YES : LTC_MP_NO;
return err;
}
}
static int set_rand(void *a, int size)
{
LTC_ARGCHK(a != NULL);
return mpi_to_ltc_error(mp_rand(a, size));
}
const ltc_math_descriptor ltm_desc = {
@ -494,6 +500,8 @@ const ltc_math_descriptor ltm_desc = {
&addmod,
&submod,
&set_rand,
};

2
src/math/tfm_desc.c
View File

@ -787,6 +787,8 @@ const ltc_math_descriptor tfm_desc = {
&addmod,
&submod,
NULL,
};

55
src/pk/rsa/rsa_exptmod.c
View File

@ -15,25 +15,28 @@
/**
@file rsa_exptmod.c
RSA LTC_PKCS exptmod, Tom St Denis
*/
*/
#ifdef LTC_MRSA
/**
Compute an RSA modular exponentiation
/**
Compute an RSA modular exponentiation
@param in The input data to send into RSA
@param inlen The length of the input (octets)
@param out [out] The destination
@param out [out] The destination
@param outlen [in/out] The max size and resulting size of the output
@param which Which exponent to use, e.g. PK_PRIVATE or PK_PUBLIC
@param key The RSA key to use
@param key The RSA key to use
@return CRYPT_OK if successful
*/
*/
int rsa_exptmod(const unsigned char *in, unsigned long inlen,
unsigned char *out, unsigned long *outlen, int which,
rsa_key *key)
{
void *tmp, *tmpa, *tmpb, *rnd, *rndi /* inverse of rnd */;
void *tmp, *tmpa, *tmpb;
#ifdef LTC_RSA_BLINDING
void *rnd = NULL, *rndi = NULL /* inverse of rnd */;
#endif
unsigned long x;
int err;
@ -41,7 +44,7 @@ int rsa_exptmod(const unsigned char *in, unsigned long inlen,
LTC_ARGCHK(out != NULL);
LTC_ARGCHK(outlen != NULL);
LTC_ARGCHK(key != NULL);
/* is the key of the right type for the operation? */
if (which == PK_PRIVATE && (key->type != PK_PRIVATE)) {
return CRYPT_PK_NOT_PRIVATE;
@ -53,7 +56,7 @@ int rsa_exptmod(const unsigned char *in, unsigned long inlen,
}
/* init and copy into tmp */
if ((err = mp_init_multi(&tmp, &tmpa, &tmpb, &rnd, &rndi, NULL)) != CRYPT_OK)
if ((err = mp_init_multi(&tmp, &tmpa, &tmpb, NULL)) != CRYPT_OK)
{ return err; }
if ((err = mp_read_unsigned_bin(tmp, (unsigned char *)in, (int)inlen)) != CRYPT_OK)
{ goto error; }
@ -67,49 +70,55 @@ int rsa_exptmod(const unsigned char *in, unsigned long inlen,
/* are we using the private exponent and is the key optimized? */
if (which == PK_PRIVATE) {
#ifdef LTC_RSA_BLINDING
if ((err = mp_init_multi(&rnd, &rndi, NULL)) != CRYPT_OK)
{ goto error; }
/* do blinding */
err = mp_rand(rnd, mp_count_bits(key->N));
if (err != CRYPT_OK) {
goto error;
goto error_blind;
}
/* rndi = 1/rnd mod N */
err = mp_invmod(rnd, key->N, rndi);
if (err != CRYPT_OK) {
goto error;
goto error_blind;
}
/* rnd = rnd^e */
err = mp_exptmod( rnd, key->e, key->N, rnd);
if (err != CRYPT_OK) {
goto error;
goto error_blind;
}
/* tmp = tmp*rnd mod N */
err = mp_mulmod( tmp, rnd, key->N, tmp);
if (err != CRYPT_OK) {
goto error;
goto error_blind;
}
#endif /* LTC_RSA_BLINDING */
/* tmpa = tmp^dP mod p */
if ((err = mp_exptmod(tmp, key->dP, key->p, tmpa)) != CRYPT_OK) { goto error; }
if ((err = mp_exptmod(tmp, key->dP, key->p, tmpa)) != CRYPT_OK) { goto error_blind; }
/* tmpb = tmp^dQ mod q */
if ((err = mp_exptmod(tmp, key->dQ, key->q, tmpb)) != CRYPT_OK) { goto error; }
if ((err = mp_exptmod(tmp, key->dQ, key->q, tmpb)) != CRYPT_OK) { goto error_blind; }
/* tmp = (tmpa - tmpb) * qInv (mod p) */
if ((err = mp_sub(tmpa, tmpb, tmp)) != CRYPT_OK) { goto error; }
if ((err = mp_mulmod(tmp, key->qP, key->p, tmp)) != CRYPT_OK) { goto error; }
if ((err = mp_sub(tmpa, tmpb, tmp)) != CRYPT_OK) { goto error_blind; }
if ((err = mp_mulmod(tmp, key->qP, key->p, tmp)) != CRYPT_OK) { goto error_blind; }
/* tmp = tmpb + q * tmp */
if ((err = mp_mul(tmp, key->q, tmp)) != CRYPT_OK) { goto error; }
if ((err = mp_add(tmp, tmpb, tmp)) != CRYPT_OK) { goto error; }
if ((err = mp_mul(tmp, key->q, tmp)) != CRYPT_OK) { goto error_blind; }
if ((err = mp_add(tmp, tmpb, tmp)) != CRYPT_OK) { goto error_blind; }
#ifdef LTC_RSA_BLINDING
/* unblind */
err = mp_mulmod( tmp, rndi, key->N, tmp);
if (err != CRYPT_OK) {
goto error;
goto error_blind;
}
#endif
} else {
/* exptmod it */
if ((err = mp_exptmod(tmp, key->e, key->N, tmp)) != CRYPT_OK) { goto error; }
@ -136,8 +145,12 @@ int rsa_exptmod(const unsigned char *in, unsigned long inlen,
/* clean up and return */
err = CRYPT_OK;
error_blind:
#ifdef LTC_RSA_BLINDING
mp_clear_multi(rnd, rndi, NULL);
#endif
error:
mp_clear_multi(tmp, tmpa, tmpb, rnd, rndi, NULL);
mp_clear_multi(tmp, tmpa, tmpb, NULL);
return err;
}