nginx and ephemeral Diffie-Hellman keys
is at rambler-co.ru
Sat Jun 14 11:22:33 MSD 2008
On Sat, Jun 14, 2008 at 08:09:13AM +0400, Igor Sysoev wrote:
> On Fri, Jun 13, 2008 at 11:13:37PM +0200, Jauder Ho wrote:
> > Patch applied and testing now.
> > >From reading the patch, it looks like the key is generated once. I did
> No, not key itself but DH parameters, those will be used to generate DH keys.
> > some more digging and reference
> > http://mail-archives.apache.org/mod_mbox/httpd-cvs/200205.mbox/%3C20020530181716.firstname.lastname@example.org%3E
> > Key should be changed out every so often.
> > - o Diffie-Hellman-Parameters for temporary keys are hardcoded in
> > - ssl_engine_dh.c, while the comment in ssl_engine_kernel.c says:
> > - "it is suggested that keys be changed daily or every 500
> > - transactions, and more often if possible."
> Nevertheless Apache still uses hardcoded DH parameters and does not allow
> to override them.
Looking in Apache repo: modern DH params in Apache/2 are 3 years old,
Apache's 1.3 DH params are 9 years old.
It's seems thare is no need to override them using ssl_dhparam.
> Actually both nginx and Apache use SSL_CTX_set_options(SSL_OP_SINGLE_DH_USE)
> and OpenSSL generate new DH key during the negotiation.
> BTW, while RSA-only case the only keys used in negotiation are
> server certificate keys, those are not changed one year.
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