Sometimes last year, Google rolled out HTTPS support for sites hosted on Blogspot which encrypts the connection between your blog and the reader. This makes it harder for hackers to track ther activities or steal information. Currently, this feature is only available to blogspot blogs on the subdomain and not custom domains. Which means if you are on.com right now it isn’t available for you (For Now).
Coming later in April 2016, the HTTPS feature will be available to Blogs that have been linked to Custom domains. So all blogs on Blogger platform can freely use encrypted connection for their blogs. This is an advancement in Google’s aim to encrypt the connections between its users and Google servers.
If your blog is still on blogspot.com and you want to try out HTTPS, simply open your blog and navigate to the Settings page. Select “yes” for “HTTPS Availability”