Over on the Stack Exchange Raspberry Pi blog, Jacob has written an excellent tutorial in which he uses Let’s Encrypt (a free certificate domain authority) to secure a website hosted on a Raspberry Pi. This means that your website(s) will be secured using https which brings a variety of security benefits. Read the tutorial here.
You may also want to check out https://caddyserver.com , which simplifies the process for you. It’s a new compliant server that uses letsencode *transparently* for you.