CSR Review Request, JDK-8163326, The default enabled cipher suites should prefer forward secrecy

[Bernd Eckenfels]

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-bounces at openjdk.java.net> im Auftrag von Xuelei Fan <xuelei.fan at oracle.com>
Gesendet: Mittwoch, März 20, 2019 6:19 AM
An: security-dev at 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-bounces at openjdk.java.net> im Auftrag
> von Sean Mullan <sean.mullan at oracle.com>
> *Gesendet:* Mittwoch, März 6, 2019 9:12 PM
> *An:* security-dev at 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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