TLS (Transport Layer Security) is a cryptographic protocol designed to provide secure communication over a computer network. It ensures the privacy and data integrity between two communicating applications, such as a web browser and a server. TLS encrypts the data exchanged, preventing eavesdropping and tampering. It also includes mechanisms for authenticating the communicating parties, often using certificates issued by trusted Certificate Authorities (CAs).
You can know if TLS is used by looking for certain indicators in your web browser or application. In web browsers, a padlock icon in the address bar and “https://” at the beginning of the URL indicate that a website is using TLS. Additionally, you can view the details of the connection, including the type of certificate and encryption being used, by clicking on the padlock icon. Many modern applications also provide settings or logs where you can check if TLS is being used for secure communication.
TLS authentication works through a process involving digital certificates and public-key cryptography. When a client connects to a server using TLS, the server presents its digital certificate, which contains its public key and is issued by a trusted CA. The client verifies the certificate against its list of trusted CAs. If the certificate is valid, the client uses the server’s public key to establish a secure session key. This session key is then used to encrypt all further communication. Optionally, client authentication can also occur, where the client presents its own certificate to the server for mutual authentication.