Transport Layer Security (TLS) is a cryptographic protocol that provides secure communication over the internet. It is the successor to the Secure Sockets Layer (SSL) protocol and is used to establish a secure connection between a client and a server.

TLS ensures the confidentiality, integrity, and authenticity of data transmitted between the client and server. It uses a combination of symmetric and asymmetric encryption algorithms to achieve these security goals. Here’s how TLS works:

1. Handshake: The client initiates a connection to the server and requests a secure connection. The server responds by sending its digital certificate, which contains its public key.

2. Certificate Verification: The client verifies the authenticity of the server’s certificate. It checks if the certificate is issued by a trusted Certificate Authority (CA) and if it has not expired or been revoked.

3. Key Exchange: The client and server perform a key exchange to establish a shared symmetric session key. This key is used for encrypting and decrypting data transmitted between them.

4. Encryption: Once the session key is established, both the client and server use it to encrypt and decrypt data. This ensures that the data remains confidential and cannot be intercepted or tampered with by unauthorized parties.

TLS also provides additional features such as server authentication, client authentication (optional), and message integrity checks using cryptographic hash functions.

TLS is widely used to secure various internet protocols, including HTTPS (secure web browsing), SMTP (secure email transmission), FTPS (secure file transfer), and more. It is continuously updated and improved to address security vulnerabilities and ensure the highest level of protection for data transmitted over the internet.