A Web browser indicates a website loaded over a secure data transfer protocol also contains insecure content by crossing off the "http://" or "https://" part of the URL in red. Google Chrome is one Web browser that uses a red strike-through to alert you about potential website security risks. Content delivered via an insecure protocol can be picked off by eavesdropping hackers.
Content Transfer Protocols
HyperText Transfer Protocol is a set of Web standards that enables devices to exchange and display Web pages. HTTP is a non-encrypted protocol that makes no attempt to conceal transferred information. Hackers can intercept HTTP data transfers to see what a user is doing on the Web and can access any information a user inputs over HTTP. HTTP Secure encrypts data transfers so that only the devices sending and receiving the information understand what's going on. HTTP is sufficient for Web browsing, but HTTPS is used whenever you're submitting personal information like passwords, credit card information and Social Security numbers.
Insecure Warning Instances
The HTTPS strike-through might occur when you're logged into a private website that handles personal information over HTTPS but handles page content like images and video over HTTP. While hackers won't be able to steal your login and personal information, they can see clues as to what you're doing on the site from the unsecured content.