SSL encryption protects online transactions by establishing a secure connection between a user's browser and a server. This technology encrypts data transmitted over the internet, preventing unauthorized access during the communication process. SSL (Secure Sockets Layer) certificates authenticate that the website is legitimate and enhances user confidence in the security of their personal information. By encrypting sensitive data like credit card details, SSL helps prevent data breaches and ensures the privacy of transactions. The presence of an SSL certificate is indicated by "https://" in a website’s URL, signaling security to users.