No, oddly my security work (mostly application security and a bit of compliance work) is not with Lisp. Although I do use Lisp to generate my documentation.
I have toyed with the idea of using Lisp to take apart binaries.
Also, Lisp wouldn't be very good with encryption, as it doesn't do constant time very well.
as regards this 10x business, i actually wasn't being very serious. it was just a playful response to the parent's claim that lisp is not suitable for large teams