In this paper, the authors will present an increased-security concept for systems administering patient-data and DICOM (Digital Imaging and COmmunication in Medicine) images. The system presented here is an intranet/internet based PACS and has been developed at the Institute of Telematics (IT) [Hlu99]. The PACS is based on standard network-protocols and has been created using DICOM - standard. See [Nem94] and [Rad99] for more information. The system components have been designed in JAVA and have been distributed onto three different computers.