On 1/4/22, 11:23, "Tomas Mraz" <tomas@xxxxxxxxxxx> wrote:
> > Theoretically, shouldn’t
> >
> > EVP_PKEY_get_int_param(pkey, OSSL_PARAM_EC_ORDER, &(unsigned int)order)
> >
> > work? I verified that it does not seem to work, at least in the
> > obvious context.
>
> OSSL_PARAM_EC_ORDER is an unsigned integer (also a bignum) and it won't
> fit into int. So that's the reason why that call fails.
In other words, the man page says it's unsigned int, but in fact it's BIGNUM? Because the pointer I gave was to "unsigned int", like in the OP's code.
This works, BTW:
if (!(ec_grp = EC_GROUP_new_by_curve_name(ECCTYPE)))
ERR("EC_GROUP_new_by_curve_name");
const BIGNUM *ord = EC_GROUP_get0_order(ec_grp);
fprintf(stderr, "order = ");
BN_print_fp(stderr, ord); fprintf(stderr, "\n");
printf("order = %s\n", BN_bn2dec(ord));
> Also the order is not a degree (maximum number of bits of a curve
> coordinate).
Yeah, I was trying to figure if *any* of EC-related parameters would work...
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