NEWS: Google search gives priority to secure sites
NEWS: When a website uses SSL (Secure Sockets Layer) / HTTPS the traffic is encrypted (The little lock in your browser usually appears) and secure. This doesn't make a website secure but is part of the solution. You can test how secure your website is here: SSL Server Test
Google has announced that it has started considering HTTPS as a metric when deciding the pagerank of a given website. Thus, all other elements being equal, HTTPS websites get preference over HTTP ones.4
Google has also indicated that it will mark HTTP websites as “unsafe”, and warn users about websites that are not using HTTPS.
To implement HTTPS a website requires a certificate, ideally regularly updated. Let's Encrypt, launched on April 12, 2016 is now providing free certificates and scripts/instructions to automate the updating of certificates.