HTTPS is also known as HTTP Secure, or it can be considered an encrypted version of HTTP. In fact, Google has already started to vigorously promote it very early, but not many responded to the support at that time. This is mainly because there are some technical barriers to migration to HTTPS, and the cost is relatively high. Secondly, no industry was promoting this change at that time.
After years of promotion, Google caught the attention of users and webmasters by tagging those sites as insecure links in Google Chrome. With Google’s efforts, 68% of traffic is currently protected on Chrome, with 81 sites using HTTPS by default on Top 100.
Starting with Chrome 68, which will go online in July of this year, all HTTP-linked sites are marked as unsafe. Hope this can further remind owners and users visit the site is not safe, further promote the upgrade of HTTPS.