WebServer can log the end client browser's ssl capabilities in the log file
By Gregory Bedigian on Nov 19, 2008
This is pretty nifty....
Apparently, the Sun WebServer can log what the end client browser's encryption capabilities. The information is picked up during the SSL Handshake.
The %Ses->client.secret-keysize% logs the browsers encryption capablity in the access log. This would be added to the format line of the access log (its the top line).