Nadim Kobeissi: > Sorry, I wasn't meaning to avoid any questions. I simply forgot to > answer them. It's best to assume good will from others on a > discussion list.
Glad to hear it. > > I do not know how many users choose forward secret protocols, nor do > I imagine there is a standardized or easy way to derive that > knowledge. This is why private keys were reset, even though we use > forward secrecy. It appears that you're using nginx - it seems reasonable to discover this information: http://mailman.nginx.org/pipermail/nginx/2010-July/021228.html http://wiki.nginx.org/NginxHttpSslModule#Built-in_variables This directs us here: "Module ngx_http_ssl_module supports the following built-in variables: "$ssl_cipher returns the cipher suite being used for the currently established SSL/TLS connection "$ssl_protocol returns the protocol of the currently established SSL/TLS connection — depending on the configuration and client available options it's one of SSLv2, SSLv3 or TLSv1 ================================= If CryptoCat is not rotating keys frequently, as some companies do for these modes, I guess that one rotation is not enough. CryptoCat is currently offering non-forward secret modes for some people - so the original concern really holds, sadly. SSL and TLS security is really painful sometimes. :( I could imagine that people who select such dangerous modes could be redirected to a page that refuses chat service until they upgrade their browser? Or perhaps something else that mitigates likely harm? That at least prevents users from potentially using TLS in a dangerous manner as they have been for quite some time. However - if no one is using them, can't you just disable them? And if many people are using them, will you ensure that they will fail closed by disabling them? Or perhaps by rotating keys on a daily basis? This seems like an important and relevant set of points: https://www.imperialviolet.org/2013/06/27/botchingpfs.html All the best, Jake _______________________________________________ cryptography mailing list cryptography@randombit.net http://lists.randombit.net/mailman/listinfo/cryptography
