A system to ensure compliance with data security standards for merchants that store, process, and transmit secure data, includes a security appliance having a global unit to monitor the functions of the security appliance, a logging unit to log data from network devices at the merchant's site and from other security appliance units, an integrity unit to construct maps of file systems of the network devices and to compare the constructed maps with previously constructed maps to detect differences between them, and a scanning unit to periodically scan the network to detect unrecognized devices on the network. The system further includes a display unit to provide compliance information on a secure basis, a back-end unit to automate and manage compliance-related tasks and data security events, and a control unit to monitor compliance performance in real-time and to implement required procedures to ensure compliance with data security standards.