The goal of this project is to characterize the most problematic constructs in widely used electronic health record (EHR) data formats by discovering and reporting parsing bugs in existing EHR management systems. Once identified, procedures will be specified for reducing existing records into a safe form that facilitates unambiguous and secure interpretation of health records, while maintaining compatibility with existing EHR systems. EHR-FIST aims to improve the security and privacy of patient data without requiring patches to the software processing that data.