[openssl-users] ECDHE Negotiation for Client but not Server

Benn Bollay benn.bollay at gmail.com
Fri Nov 13 21:41:57 UTC 2015

Sorted; needed to call SSL_CTX_set_tmp_ecdh with my private EC_KEY.  Can
someone express an opinion if using my private key is acceptable there, or
if I should generate a new one from a named curve each time I create a


On Fri, Nov 13, 2015 at 11:21 AM, Benn Bollay <benn.bollay at gmail.com> wrote:

> Hi folks -
> Tested against OpenSSL 1.0.1f and 1.0.1p (but with modifications).
> I've got some code that creates an SSL_CTX (http://pastebin.com/XveDvvch)
> that works fine for negotiating ECDHE-* ciphers as a client when talking to
> an s_server, but fails as a server both when accepting connections from
> itself or from s_client with a no shared cipher error.
> You can download a full package to reproduce the issue at
> http://www.magitech.org/gambit/ecdhetest.tar.gz
> You can run the test by using make:
>   $ make all
>   $ make s_server & # Run’s OpenSSL s_server in the background
>   $ make t_client # Runs the client - should be able to see the handshake
> complete on the server’s log window.
>   $ make t_server & # After killing the s_server, start up the test server
>   $ make s_client # Fails to negotiate.
> Any suggestions?
> Cheers,
> --B
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