Ivan Ristic is a security researcher, engineer, and author who is the developer of ModSecurity, an open source web application firewall, and is known for his SSL/TLS and PKI research, tools and guides published on the SSL Labs web site.
You'll often find him speaking at security conferences such as Black Hat, RSA, OWASP AppSec, etc.
http://blog.ivanristic.com/
https://twitter.com/ivanristic
http://www.amazon.com/Ivan-Ristic/e/B001KDZVKU
http://www.oreilly.com/pub/au/1360