Transport Layer Security (TLS) is a security protocol that is widely used to encrypt internet traffic and to secure the communication between clients and servers. TLS is the successor to Secure Sockets Layer (SSL), and the two protocols are often referred to interchangeably.
TLS works by establishing an encrypted connection between the client and the server and exchanging a series of messages to verify the identity of the server and to establish the encryption keys that will be used to secure the communication. TLS uses public key cryptography to establish the encryption keys and to verify the server’s identity.
TLS is commonly used to protect sensitive internet communication, such as online banking, shopping, and accessing personal information. To use TLS, a website must obtain and install an SSL/TLS certificate from a trusted certificate authority (CA). The certificate contains the website’s public key and a digital signature that verifies the website’s identity.
TLS is indicated by the “https://” prefix in the URL of a website and by a padlock icon in the web browser. Many web browsers also display a green padlock icon to indicate that a website is using an extended validation (EV) SSL/TLS certificate, which provides additional security and trust.