On Tue, Sep 03, 2013, Viktor Dukhovni wrote: > On Tue, Sep 03, 2013 at 03:16:06PM +0200, Dr. Stephen Henson wrote: > > The Postfix user (that is email administrator) interface does not > require users to know much or anything at all about the various EECDH > curves. The administrator chooses one of: > > # default "strong" > smtpd_tls_eecdh_grade = none | strong | ultra > > and behind the scenes Postfix TLS library parameters with defaults > that only expert users would ever consider changing set: > > tls_eecdh_strong_curve = prime256v1 > tls_eecdh_ultra_curve = secp384r1 >
The SSL_CONF_cmd interface in OpenSSL 1.0.2 and later might be useful too. It's designed to provide a common format for configuration. > > For OpenSSL 1.0.2 the EC curve negotiation has been overhauled. Both client > > and server can set curve preferences and by calling: > > > > SSL_CTX_set_ecdh_auto(ctx, 1); > > > > the curve to use is handled automatically. > > That sounds like a substantial improvement. However, I notice that > this too is undocumented. :-( > It was documented on my hard disk, I just forgot to push it, oops. It's included in commit c3eb33763bf2999843fe4124f3f39dea6edc26e6 > Should there also be an SSL_CTX_set_dh_auto(ctx, 1)? With suitable > compiled-in MODP groups (perhaps from RFC 5114, though there is I > think no gain from the DSA-style subgroups in TLS since "q" is not > sent to the client). > There is some gain server side during key generation, but nothing client side. Steve. -- Dr Stephen N. Henson. OpenSSL project core developer. Commercial tech support now available see: http://www.openssl.org ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
