On 5/23/2015 9:50 PM, Bernd Eckenfels wrote: > Am Sat, 23 May 2015 08:30:26 +0800 > schrieb Xuelei Fan <xuelei....@oracle.com>: > >> Please refer to the "Customizing Size of Ephemeral Diffie-Hellman >> Keys" section of JSSE Reference Guide. >> >> http://docs.oracle.com/javase/8/docs/technotes/guides/security/jsse/JSSERefGuide.html > > Thanks Xulei, but I think this does not address the minimum accepted > size of an client SSLSocket (at least I could not see that in the > description). It only allows to configure the server generated groups > in the ServerKeyExchange. > > When setting jdk.tls.ephemeralDHKeySize=2048 I still can connect to > https://dhe512.zmap.io/ > Right, it is impact the generation of DH keys.
I did not get your ideas in the previous mail. "jdk.tls.disabledAlgorithms" is expected to work to disable weak DH keys (for example, ""DHE keySize < 768"). Can you describe your concern more? Thanks, Xuelei > Gruss > Bernd > > BTW in Regards to the Server side: > > That document should mention that the parameter group is generated > randomly on first use (matching DSA restrictions). It is a good thing > there are no standard primes used, it would be better if they are > constructed not specifically for DSA (as mentioned in the Logjam > paper). > > I can imagine that in the future for higher security mutual agreed > parameter groups become more important, so let me point to > http://bugs.java.com/view_bug.do?bug_id=4641806 as well. >
