Abstract: A system and a method are described for accessing, according to selection criteria and security rules, secure information from a set of secret data, mainly in a medical system for patient data. A performance problem arises when applying the security rules first, followed by the selection criteria. A solution is to perform the selection step first, followed by application of the security rules. The method may be used in a computer or server system e.g. for scheduling examinations of patients in a radiology department or for documentation purposes of these examinations.