Migrating site from HTTP protocol to HTTPS (Hypertext Transfer Protocol Secure) protocol will help to add additional ranking signal as Google officially announced. HTTPS is an internet communication protocol that protects the integrity and confidentiality of data between the user’s computer and the site. Users expect a secure and private online experience when using a website. We encourage you to adopt HTTPS in order to protect your users’ connection to your website, regardless of the content on the site.
HTTPS is useful for sites that collect and transmit personal information. Banks, e-commerce sites, social networks and online schools need to have HTTPS in place to make sure consumers’ sensitive information is protected. For more visit at Search Engine Traffics blog website. Reference link of Google’s Official announcement