[openssl-dev] ECDH engine

[Dr. Stephen Henson]

On Fri, Dec 18, 2015, Alexander Gostrer wrote:

> Hi Steve,
> 
> John and I completed writing an ECDH engine based on the
> OpenSSL_1_0_2-stable branch. We were planning to expand it to the master
> but found some major changes made by you recently. What is the status of
> this task? Is it stable enough to follow it? Are you planning another
> changes? Is there a design document that we can use in our work?
> 

The version in master shouldn't change much any more. Documentation will be
available in the near future. The changes were meant to remove some of the
weird "quirks" of ECC compared to other algortihms and to permit future
expansion to a wider range of curves.

In the meantime it shouldn't be too hard to follow how the new code works.
Instead of separate ECDH/ECDSA methods with weird locking and ex_data and
minimal ENGINE support everything is combined into a single EC_KEY_METHOD
which can contain ECDSA, ECDH and key generation (something which was
impossible with the old code) and be tied directly to an ENGINE.

Most of the primary APIs such as ECDH_compute_key can be redirected directly
through an engine supplied function in EC_KEY_METHOD.

Having said that the code is very new and may have the odd bug that needs to
be fixed. If you have any problems let me know and I'll look into them.

Steve.
--
Dr Stephen N. Henson. OpenSSL project core developer.
Commercial tech support now available see: http://www.openssl.org