On Fri, Mar 18, 2016 at 06:59:36PM +0000, Blumenthal, Uri - 0553 - MITLL wrote:
> Answered my own question: should use EVP_PKEY_bits(pkey) instead.
That's not the right way to determine the curve id.
> >How do I determine what curve the above key is on?
For that you need to determine the EVP_PKEY algorithm type:
int type = EVP_PKEY_base_id(pkey);
if (type == EVP_PKEY_EC) {
EC_KEY *key = EVP_PKEY_get0_EC_KEY(pkey);
EC_GROUP *group = EC_KEY_get0_group(key);
/* Use that group to generate more points */
}
So you don't need code to specifically identify the group, but if
you want to constrain the supported groups:
switch (EC_GROUP_get_curve_name(group)) {
case NID_undef:
default:
/* Unknown or not named group */
case NID_X9_62_prime256v1:
/* P-256 */
...
case NID_secp384r1:
/* P-384 */
...
}
--
Viktor.
