It is the secure version of http protocol, http is the primary protocol used to send data between a web browser and webservers. HTTPS is encrypted form of HTTP to increase the data transfer security. Its very import for sensitive data, such as by logging into a bank account, email service, or health insurance provider.
Websites those need login credentials, should use HTTPS. In modern web browsers such as Chrome, websites that do not use HTTPS are marked differently than those that are. Web browsers like chrom, mozilla, MS Edge takes HTTPS seriously.
How HTTPS Works ?
HTTPS uses an Encryption protocol to encrypt the data exchange between client and webserver. This protocol is called TLS i.e Transport Layer Security [Latest version is TLS 1.3 released in 2018], Earlier it was known as SSL i.e Secure Socket Layer. This protocol use the cryptographic scheme known as an Asymmetric public key infrastructure. It uses two different keys to encrypt communications between sender and receiver i.e. between two parties, the sequence is like :
Private key – This key is owned by webserver and is kept securely. It is used to decrypt information encrypted by the public key.
Public key – This key is available for everyone who wants to interact with the Web Server in a secure way. Browser encrypt the data with public key and this can be decrypted only by the webserver owning the private key, making this communication secure.