View source for Creating an OpenSSL Engine to use indigenous ECDH ECDSA and HASH Algorithms

=Note about the ECDSA_METHOD structure=
Instead of putting the definition of the <tt>ECDSA_METHOD</tt> in the header file we can alternatively use the build-in OpenSSL methods for acquiring the method structure. Actually this is encouraged with OpenSSL versions >= 1.0.2. This is done as follows:
<pre>
static ECDSA_METHOD *oezgan_engine_ecdsa_method = NULL

 static int setup_ecdsa_method(void)
  {
        oezgan_engine_ecdsa_method = ECDSA_METHOD_new(NULL);
	if (oezgan_engine_ecdsa_method == NULL)
            return 0;

        ECDSA_METHOD_set_name(oezgan_engine_ecdsa_method, "Oezgan engine ECDSA method");
        ECDSA_METHOD_set_sign(oezgan_engine_ecdsa_method, oezgan_engine_ecdsa_sign);
        ECDSA_METHOD_set_sign_setup(oezgan_engine_ecdsa_method, oezgan_engine_ecdsa_sign_setup);
        ECDSA_METHOD_set_verify(oezgan_engine_ecdsa_method, oezgan_engine_ecdsa_do_verify);
	return 1;
    }
</pre>

and then in the bind_helper we have to do something like this:
<pre>
    int bind_helper(ENGINE * e, const char *id)
    {
        if (!ENGINE_set_id(e, engine_oezgan_id) ||
                !ENGINE_set_name(e, engine_oezgan_name) ||
		!setup_ecdsa_method() ||
                !ENGINE_set_ECDSA(e, oezgan_engine_ecdsa_method)
        )
            return 0;
        return 1;
    }
</pre>

This is probably the smoother way to go.