Online casinos manage player data securely through a multi-layered approach that incorporates advanced security technologies and strict data management policies. They utilize encryption methods, such as Secure Socket Layer (SSL) technology, to protect sensitive information during transmission, ensuring that data exchanged between players and the casino remains confidential. Access controls are enforced, limiting data access to authorized personnel only, while regular security audits and vulnerability assessments are conducted to identify and address potential weaknesses in their systems.