From: "Carlo E. Prelz" <fluido@...>
Date: 2012-10-28T04:44:27+09:00
Subject: Re: OpenSSL ECDSA public key from private

	Subject: Re: OpenSSL ECDSA public key from private
	Date: Sun 28 Oct 12 04:23:52AM +0900

Quoting Nokan Emiro (uzleepito@gmail.com):

> So what I need is to ask the 'key' object to be so kind and calculate the
> the
> public key for me using my private key I've just set with #private_key=.
> 
> key.private_key =   *<a paramether from outside>*
> *
> *
> key.plese_calculate_the_public_key_from_the_private_one!

I had a look at the ruby code. #generate_key just calls openssl
function "EC_KEY_generate_key". From  openssl.sourcearchive.com, I see
that, within that function, the public key is generated with

      if (eckey->pub_key == NULL)
            {
            pub_key = EC_POINT_new(eckey->group);
            if (pub_key == NULL)
                  goto err;
            }

EC_POINT_new is used within Ruby when creating an
OpenSSL::PKey::EC::Point object, when passing it a 'group'. Now, I
have no idea what a group is, but your key has a 'group'. And it is
populated, even without calling #generate_key.

If I run 

pub_key=OpenSSL::PKey::EC::Point.new(key.group)

I get something. Again, I hope this is what you are looking for.

Carlo

-- 
  *         Se la Strada e la sua Virtu' non fossero state messe da parte,
* K * Carlo E. Prelz - fluido@fluido.as             che bisogno ci sarebbe
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