The technology often employed for secure online payment transactions is Secure Socket Layer (SSL) or its successor, Transport Layer Security (TLS). These protocols encrypt data exchanged between a user's browser and the web server, ensuring that sensitive information such as credit card numbers, account details, and personal information remains confidential during transmission. SSL/TLS also authenticates the server to verify its identity, protecting users against phishing attacks. This secure environment is crucial for maintaining trust in e-commerce and facilitating safe online transactions.