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. Regards, Brian From: twitter-development-talk@googlegroups.com [mailto:twitter-development-t...@googlegroups.com] On Behalf Of Bob Lord Sent: Monday, May 24, 2010 7:43 PM To: twitter-development-talk@googlegroups.com Subject: Re: [twitter-dev] DHE ciphersuites disabled? We're talking about this internally. I'm cautiously optimistic. /B On Mon, May 24, 2010 at 12:43 AM, Brian Smith <br...@briansmith.org> wrote: I noticed about a week ago that my application stopped working. Now I have tested it and it appears that api.twitter.com 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 api.twitter.com -port 443 -tls1 -cipher DHE-RSA- AES128-SHA openssl s_client -host api.twitter.com -port 443 -tls1 -cipher DHE-RSA- AES256-SHA openssl s_client -host api.twitter.com -port 443 -tls1 -cipher AES128-SHA openssl s_client -host api.twitter.com -port 443 -tls1 -cipher AES256-SHA Thanks, Brian
