When you connect to most websites, your web browser uses the standard HTTP protocol. HTTPS is the secure, encrypted counterpart to HTTP it literally stands for “HTTP Secure,” which is “Hypertext Transfer Protocol Secure”
Hypertext Transfer Protocol Secure (HTTPS) is a communications protocol for secure communication over a computer network, with especially wide deployment on the Internet. Technically, it is not a protocol in and of itself; rather, it is the result of simply layering the Hypertext Transfer Protocol (HTTP) on top of the SSL/TLS protocol, thus adding the security capabilities of SSL/TLS to standard HTTP communications. The main motivation for HTTPS is to prevent wiretapping and man-in-the-middle attacks.
The security of HTTPS is therefore that of the underlying TLS, which uses long-term public and secret keys to exchange a short term session key to encrypt the data flow between client and server. An important property in this context is perfect forward secrecy (PFS), so the short-term session key cannot be derived from the long-term asymmetric secret key; however, PFS is not widely adopted
You Should Care
HTTPS is important whenever you’re logging into something or giving payment details. If you’re about to enter a password or other personal information, check your address bar and ensure that you’re on an HTTPS site. If you’re not, it’s not really safe to enter such sensitive data. Most websites should be doing this properly now, but a badly coded site may still send your sensitive data in unsecured plain-text if it’s set up to connect over HTTP.
HTTPS is also valuable because it provides some verification of website identities. If you’re using an unfamiliar network and you connect to your bank’s website, ensure that you see the HTTPS and the correct website address. This helps you ensure that you’re actually connected to the bank’s website, although it’s not a foolproof solution. If you don’t see an HTTPS indicator on the login page, you may be connected to an impostor website on a compromised network.
From : howtogeek