Why do websites need https?

Everyone knows a popular online saying and the famous cartoon "on the Internet, no one knows that you are a dog":

This is dangerous for online shopping and e-commerce, because you cannot and should not believe that the so-and-so company (brand) called by the website is your real-world company (brand). At the same time, the IP technology used by the Internet is to transmit all the information in clear text, which makes it possible for anyone else to see all the confidential information you submit on the website without any encryption measures, because there are many routes from your computer to the website server, and many people have access to the transmission route. It is possible to illegally intercept or even tamper with your confidential transaction information (especially bank card information).

And https is a secure http connection, and s is secure, that is, if the URL of the browser address bar of the page you are browsing is preceded by https:// (usually the website is http://), it means that any information you enter on this URL is encrypted from your computer to the web server. Only in this way can we ensure that the confidential information you submit on the website is automatically encrypted and transmitted to the website server and will not be illegally intercepted or tampered with.

In order to give users an eye-catching understanding (users often do not pay attention to http:// or https://), the browser makes an obvious security lock flag. Take IE browser as an example, as shown in figure 1 below, the security lock flag of IE version 10 browser is displayed in the lower right corner of the status bar. Mouse over the security lock will display the encryption strength currently used (figure 128bit):