Google already warned unencrypted sites earlier this year that all HTTP connection-based webpages will be prominently marked as "Not Secure" beginning in July once Chrome 68 launches. That version of Google's web browser is set for rollout on July 24, which means all insecure sites will begin to face mounting pressure to switch to using HTTPS.
Initially, the "Not Secure" warning began to be displayed in the address bar for HTTP sites that collect passwords and credit card information. Later, it was implemented on portals where any data was entered over an insecure connection and on all HTTP pages visited in Incognito mode. With the new changes, Google will start condemning all insecure sites that continue to stick to the HTTP configuration.
HTTPS is designed to encrypt the connection between your computer and the site you visit so that information being transmitted remains protected from the prying eyes and interference of third-parties. The wider rollout of the warning message on HTTP sites marks a significant step in Google's efforts to get every website to embrace HTTPS as its default protocol for secure communication instead of being just an option.
Google also plans to remove the "Secure" label on HTTPS web pages in Chrome 69 which is set for release in September. While some users may see it as a backward move, Google is hoping that by removing Chrome’s positive security indicator, it will give users the idea that the web is safe by default.
Source: Android Police