Good to understand now.

Do you want to add a sentence how devs&ops can change the order (I.e. enabling 
the ciphers in a different order?)

Just to be clear, In the Risk Evaluation the „should have been used“ does mean 
JDK should have done this before, it does not mean it has used the preference 
before, right? (Although in practice I guess especially DHE have been prefered 
over RSA by peers often)

The main risk of the change to me seems to be: priotizing DHE over plain 
DSS/RSA. As this increases the likelyhood for DHE related interop problems (due 
to lack of negotiation of „group“ sizes).

I suspect two aspects reduce the risk, but maybe it should be mentioned 
explicitely:

„Preference of DHE_RSA over RSA could increase group/size related 
interoperability problems. However it is expected that this is mitigated by the 
additional DHE parameters (FFDHE) in group announcement and also the fact that 
existing implementations have been confronted with bigger DHE keys for some 
time now. Besides many existing servers prefer ECDHE or would have picked DHE 
over RSA anyway.“

I would expect no performance impact as most modern/perfcritical systems would 
use ECDHE already (and the perf impact of preferring GCM over CBC is a 
different discussion)


Gruss
Bernd
--
http://bernd.eckenfels.net

________________________________
Von: security-dev <security-dev-boun...@openjdk.java.net> im Auftrag von Xuelei 
Fan <xuelei....@oracle.com>
Gesendet: Mittwoch, März 20, 2019 6:19 AM
An: security-dev@openjdk.java.net
Betreff: Re: CSR Review Request, JDK-8163326, The default enabled cipher suites 
should prefer forward secrecy

Hi,

I extended this CSR to cover more update, and update per the comments.
Please let me know your concerns by the end of March 21, 2019.

Thanks,
Xuelei

On 3/6/2019 3:41 PM, Bernd Eckenfels wrote:
> I am not clear on what would „preferred in current default context“
> mean. Does that mean it preferred the PFS ciphers anyway.. for suggested
> order in client handshake? as server? And what would be the non-Default
> context. Is this „TLS“ context?
>
> Gruss
> Bernd
> --
> http://bernd.eckenfels.net
> ------------------------------------------------------------------------
> *Von:* security-dev <security-dev-boun...@openjdk.java.net> im Auftrag
> von Sean Mullan <sean.mul...@oracle.com>
> *Gesendet:* Mittwoch, März 6, 2019 9:12 PM
> *An:* security-dev@openjdk.java.net
> *Betreff:* Re: CSR Review Request, JDK-8163326, The default enabled
> cipher suites should prefer forward secrecy
> Hi Xuelei,
>
> In the Specification section, I think it would be useful to note which
> cipher suites are forward secret and which are not. Otherwise, it is
> difficult to see what has changed, since there are so many supported
> suites. Perhaps in parentheses, ex:
>
> TLS_AES_128_GCM_SHA256 (forward secret)
> ...
>
> I also think you should summarize what has changed or what is roughly
> the new order, for example:
>
> - The TLS_RSA suites have moved down ...
> - The TLS_ECDH suites have moved
> - The SSL_RSA suites have moved down ...
> etc...
>
> --Sean
>
> On 2/21/19 4:45 PM, Xuelei Fan wrote:
> > Hi,
> >
> > Could I get the CSR reviewed?
> >     https://bugs.openjdk.java.net/browse/JDK-8219545
> >
> > It is proposed to increase the priority of forward secrecy cipher
> > suites, and decrease the priority of RSA key exchange based cipher
> > suites for the default enabled cipher suites in the SunJSSE provider.
> >
> > Thanks,
> > Xuelei

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