Google starting to index HTTPS pages by default

The most impotent policy of Google is user security on top priority. Google officially announced index HTTPS pages by default from now on.It mean Google-bot will start crawling HTTPS equivalents of HTTP pages.

Google say at Official blog-As a natural continuation of this, today we'd like to announce that we're adjusting our indexing system to look for more HTTPS pages. Specifically, we’ll start crawling HTTPS equivalents of HTTP pages, even when the former are not linked to from any page.

When two URLs from the same domain appear to have the same content but are served over different protocol schemes, we’ll typically choose to index the HTTPS URL if:

• It doesn’t contain insecure dependencies.
• It isn’t blocked from crawling by robots.txt.
• It doesn’t redirect users to or through an insecure HTTP page.
• It doesn’t have a rel="canonical" link to the HTTP page.
• It doesn’t contain a noindex robots meta tag.
• It doesn’t have on-host outlinks to HTTP URLs.
• The sitemaps lists the HTTPS URL, or doesn’t list the HTTP version of the URL
• The server has a valid TLS certificate.

From - https://googlewebmastercentral.blogspot.in/2015/12/indexing-https-pages-by-default.html

Index HTTPS pages

We know HTTPS is secure version of the HTTP protocol used on the Internet to connect users to website. Google want to encouraging webmasters to redirect their HTTP site to the HTTPS version for security and batter performance.Using HTTPS encryption should protect users against content injection attacks, which can happen over insecure connections.

Mark say - I noticed this for several weeks. I rewrote canonical rules to default to https and submitted https URI through the XML sitemaps. I then set https to default in Magento and saw huge rankings in two or our three sites. I'm still struggling with adding and forcing https via headers and htaccess redirects but my http links are now history.