SSL/TLS secures online communications through a combination of encryption, authentication, and integrity checks. When a user connects to a secure website, SSL/TLS establishes an encrypted link between the user's browser and the web server, ensuring that any data exchanged remains confidential. These protocols also validate the server's identity using digital certificates, which helps build trust with users. By employing advanced cryptographic techniques, SSL/TLS protects against eavesdropping and tampering, safeguarding sensitive information during online interactions.