BN_BLINDING *BN_BLINDING_new(const BIGNUM *A, const BIGNUM *Ai, BIGNUM *mod)
	{
	BN_BLINDING *ret=NULL;

	bn_check_top(mod);

	if ((ret=(BN_BLINDING *)OPENSSL_malloc(sizeof(BN_BLINDING))) == NULL)
		{
		BNerr(BN_F_BN_BLINDING_NEW,ERR_R_MALLOC_FAILURE);
		return(NULL);
		}
	memset(ret,0,sizeof(BN_BLINDING));
	if (A != NULL)
		{
		if ((ret->A  = BN_dup(A))  == NULL) goto err;
		}
	if (Ai != NULL)
		{
		if ((ret->Ai = BN_dup(Ai)) == NULL) goto err;
		}

	/* save a copy of mod in the BN_BLINDING structure */
	if ((ret->mod = BN_dup(mod)) == NULL) goto err;
	if (BN_get_flags(mod, BN_FLG_CONSTTIME) != 0)
		BN_set_flags(ret->mod, BN_FLG_CONSTTIME);

	ret->counter = BN_BLINDING_COUNTER;
	return(ret);
err:
	if (ret != NULL) BN_BLINDING_free(ret);
	return(NULL);
	}