Online payment systems ensure transaction security through various measures, including encryption, tokenization, and secure payment gateways. Encryption protects sensitive information, such as credit card details, by converting it into unreadable code for unauthorized parties. Tokenization replaces this sensitive data with unique tokens, minimizing the risk of exposure. Secure payment gateways act as intermediaries to verify and authorize transactions. Additionally, compliance with global standards, like PCI DSS (Payment Card Industry Data Security Standard), ensures that payment systems adopt best practices for safeguarding user data.