This article will guide you how to convert SSL Nginx cert to Tomcat cert. Nginx cert and Tomcat cert When you buy SSL cert for Nginx web server (or Apache), you usually get 3 files of the following type: STAR_domain.CERT.crt STAR_domain.PRIVATE.key STAR_domain.CA.key Nginx’s ssl cert file uses X.509 format. You can read more about it.