You might have noticed that browsers have recently started to place symbols (colored padlocks) to grade the level of safety of the websites.
Look at the web address: on the left, you will find symbols indicating the safety status. There are three types of symbols. Small green padlocks stand for secured websites, information or grey symbols may be found when the website is only partially secured; and red warning symbols make users aware that the information exchanged on the website is not secure.
The secure website have SSL certificates (Secure Sockets Layer). The Certification Authority that issues these certificates performs a prior check on the relevant website to verify its security.