Thanks for the response, Bob.


I know a fair amount about this kind of thing. Feel free to contact me you'd
like any more information or suggestions on a good ephemeral Diffie-Hellman
parameters and/or ways of mitigating the TLS handshake performance costs.





[] On Behalf Of Bob Lord
Sent: Monday, May 24, 2010 7:43 PM
Subject: Re: [twitter-dev] DHE ciphersuites disabled?


We're talking about this internally. I'm cautiously optimistic. 


On Mon, May 24, 2010 at 12:43 AM, Brian Smith <> wrote:

I noticed about a week ago that my application stopped working. Now I have
tested it and it appears that is now blocking DHE cipher
suites such as TLS_DHE_RSA_WITH_AES_128_CBC_SHA, whereas previously these
DHE cipher suites were working perfectly. The DHE cipher suites have a
distinct security advantage over the non-DHE cipher suites like
TLS_RSA_WITH_AES_128_CBC_SHA: in the event that Twitter's RSA private key is
compromised (via hacking, a warrant, a court order, or other means), all the
previous traffic encrypted with the non-DHE cipher suites can be decrypted,
but the previous traffic encrypted with DHE cipher suites cannot be
decrypted after the fact.


My questions:


1.      Is there any chance the DHE cipher suites can be re-enabled?

2.      Can you provide any guarantees about which cipher suites will always
be available?


openssl s_client -host -port 443 -tls1 -cipher DHE-RSA-

openssl s_client -host -port 443 -tls1 -cipher DHE-RSA-

openssl s_client -host -port 443 -tls1 -cipher AES128-SHA

openssl s_client -host -port 443 -tls1 -cipher AES256-SHA





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