BIGNUM *BN_mod_inverse(BIGNUM *in,
const BIGNUM *a, const BIGNUM *n, BN_CTX *ctx)
{
BIGNUM *rv;
int noinv;
rv = int_bn_mod_inverse(in, a, n, ctx, &noinv);
if (noinv)
BNerr(BN_F_BN_MOD_INVERSE,BN_R_NO_INVERSE);
return rv;
}
BN_BLINDING *BN_BLINDING_create_param(BN_BLINDING *b,
const BIGNUM *e, BIGNUM *m, BN_CTX *ctx,
int (*bn_mod_exp) (BIGNUM *r,
const BIGNUM *a,
const BIGNUM *p,
const BIGNUM *m,
BN_CTX *ctx,
BN_MONT_CTX *m_ctx),
BN_MONT_CTX *m_ctx)
{
int retry_counter = 32;
BN_BLINDING *ret = NULL;
if (b == NULL)
ret = BN_BLINDING_new(NULL, NULL, m);
else
ret = b;
if (ret == NULL)
goto err;
if (ret->A == NULL && (ret->A = BN_new()) == NULL)
goto err;
if (ret->Ai == NULL && (ret->Ai = BN_new()) == NULL)
goto err;
if (e != NULL) {
BN_free(ret->e);
ret->e = BN_dup(e);
}
if (ret->e == NULL)
goto err;
if (bn_mod_exp != NULL)
ret->bn_mod_exp = bn_mod_exp;
if (m_ctx != NULL)
ret->m_ctx = m_ctx;
do {
int rv;
if (!BN_rand_range(ret->A, ret->mod))
goto err;
if (!int_bn_mod_inverse(ret->Ai, ret->A, ret->mod, ctx, &rv)) {
/*
* this should almost never happen for good RSA keys
*/
if (rv) {
if (retry_counter-- == 0) {
BNerr(BN_F_BN_BLINDING_CREATE_PARAM,
BN_R_TOO_MANY_ITERATIONS);
goto err;
}
} else
goto err;
} else
break;
} while (1);
if (ret->bn_mod_exp != NULL && ret->m_ctx != NULL) {
if (!ret->bn_mod_exp
(ret->A, ret->A, ret->e, ret->mod, ctx, ret->m_ctx))
goto err;
} else {
if (!BN_mod_exp(ret->A, ret->A, ret->e, ret->mod, ctx))
goto err;
}
return ret;
err:
if (b == NULL) {
BN_BLINDING_free(ret);
ret = NULL;
}
return ret;
}