[openssl-users] Naive: how to generate EC public key from EC private key?

[Viktor Dukhovni]

> On Mar 20, 2016, at 10:32 PM, Blumenthal, Uri - 0553 - MITLL <uri at ll.mit.edu> wrote:
> 
> dup_ekey = EVP_PKEY_get1_EC_KEY(pubkey);
> group = (EC_GROUP*) EC_KEY_get0_group(dup_ekey);

Declare the group as:

	const EC_GROUP *group;

Then:

	group = EC_KEY_get0_group();

> nid = EC_GROUP_get_curve_name(group);
> printf("wrap: Deriving ECC keys over curve \"%s\"\n",
> EC_curve_nid2nist(nid));

This is fine.


> EC_GROUP_free(group);

This is very wrong.  You're not supposed to free the group.
Note the "get0_group", you're not getting a copy...

-- 
	Viktor.