OFFIS develops in cooperation with the company M-SPEC GmbH and the pediatric clinic of Freiburg a scientific medical archive for the expert network "SKELNET", a project funded by the German Federal Ministry of Education and Research.(BMBF). The SKELNET system is designed to investigate skeletal dysplasia, which are different forms of dwarfism (microsomia). The centralized SKELNET archive is going to store medical images (e.g. CT or MR images) which can be sent from different clinics in Germany. The archive offers pseudonymized image access for researchers as well as full access including patient identifying information for the attending physician(s). For offering such services, high pricacy requirements have to be met by the SKELNET architecture. Therefore medical and identifying information are stored in different geographical locations and need to be merged ad hoc. OFFIS - being an expert for the medical imaging standard DICOM - is responible for pseudonymizing and re-identifying DICOM data as well as implementing the corresponding DICOM network services.