Typically when landing on an unsecured website you are greeted with a grey information icon in the address bar. You have to click into the icon which then tells you that the site is not secure and that you should not give out any sensitive information.
The reason for this is, the site is not using HTTPS (Hyper Text Transfer Protocol Secure). Meaning the information sent from the website to a server is non-encrypted. When data is non-encrypted it makes it easier for attackers to snoop on your data packets and retrieve sensitive information such as credit or debit card numbers. HTTPS is particularly important for sites that use online banking and online shopping forms.
On the other hand, when you land on a secure site you are greeted with a green lock icon letting you know that the site is encrypted and is “safe”.
According to a chromium blog google plans on showing a red icon letting the user know that the site is not safe. And displaying nothing when the site is safe. The reason? Most users should expect that the web is safe to browse by default. And should be alerted when it is not.