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Add blinding of mod inverse to RSA key gen

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This commit is contained in:
Sean Parkinson
2019-12-20 12:12:38 +10:00
parent 51f956490f
commit 9d94b48056
1 changed files with 29 additions and 0 deletions
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29
wolfcrypt/src/rsa.c
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@ -4026,13 +4026,42 @@ int wc_MakeRsaKey(RsaKey* key, int size, long e, WC_RNG* rng)
err = mp_sub_d(&p, 1, &tmp1);
if (err == MP_OKAY) /* tmp2 = q-1 */
err = mp_sub_d(&q, 1, &tmp2);
#ifndef WC_RSA_BLINDING
if (err == MP_OKAY) /* tmp3 = order of n */
err = mp_mul(&tmp1, &tmp2, &tmp3);
#else
if (err == MP_OKAY) /* tmp3 = lcm(p-1, q-1), last loop */
err = mp_lcm(&tmp1, &tmp2, &tmp3);
#endif
/* make key */
if (err == MP_OKAY) /* key->e = e */
err = mp_set_int(&key->e, (mp_digit)e);
#ifdef WC_RSA_BLINDING
/* Blind the inverse operation with a value that is invertable */
if (err == MP_OKAY) {
do {
err = mp_rand(&key->p, get_digit_count(&tmp3), rng);
if (err == MP_OKAY)
err = mp_set_bit(&key->p, 0);
if (err == MP_OKAY)
err = mp_set_bit(&key->p, size - 1);
if (err == MP_OKAY)
err = mp_gcd(&key->p, &tmp3, &key->q);
}
while ((err == MP_OKAY) && !mp_isone(&key->q));
}
if (err == MP_OKAY)
err = mp_mul_d(&key->p, (mp_digit)e, &key->e);
#endif
if (err == MP_OKAY) /* key->d = 1/e mod lcm(p-1, q-1) */
err = mp_invmod(&key->e, &tmp3, &key->d);
#ifdef WC_RSA_BLINDING
/* Take off blinding from d and reset e */
if (err == MP_OKAY)
err = mp_mulmod(&key->d, &key->p, &tmp3, &key->d);
if (err == MP_OKAY)
err = mp_set_int(&key->e, (mp_digit)e);
#endif
if (err == MP_OKAY) /* key->n = pq */
err = mp_mul(&p, &q, &key->n);
if (err == MP_OKAY) /* key->dP = d mod(p-1) */