The "simple security property" is a concept in computer security that ensures a subject (like a user or process) cannot read data at a higher security level than their own. This means that if a user has a lower clearance, they cannot access sensitive information that is classified at a higher level. This property helps prevent unauthorized access to confidential data. This principle is part of the broader Bell-LaPadula model, which focuses on maintaining data confidentiality. By enforcing the simple security property, organizations can protect sensitive information and reduce the risk of data breaches, ensuring that only authorized users can access specific data.