Get cipher used for HTTPS with nginx

Question

Background

I would like to run several Tornado instances with nginx as a load balancer and static file server. Since both are to be running on the same machine (or atleast the same, private network) I would like nginx to handle HTTPS connections and have it communicate with the tornado instances without encryption. I found how to configure nginx to do that and how to set an X-Scheme header, allowing me to check if the connection was via HTTP or HTTPS.

Question

What I would like is to also get information about the cipher used, so that I can display a notification to the user if their browser does not support PFS yet. Is there a way to do this?

Answer 1

http://nginx.org/en/docs/http/ngx_http_ssl_module.html#variables first variable is $ssl_cipher