The increasing computational power of embedded systems allows the usage of various applications in one system. These applications may possess diverse safety requirements and have to be classified into different criticality levels. Systems that execute applications of different criticality levels are called Mixed-Criticality Systems (MCSs). In addition to the increasing computational power of embedded systems, there is the trend to interconnect the individual MCSs to distributed MCS. Assuring the safety of a system protects against unintended faults. Intentional faults are often not covered by safety. They may also lead to a failure of the system. To protect the system against intentional faults, security services have to be used. Hence, there is no safety without security. The dependability of the communication is important in safety critical systems. The usage of secure communication services can prevent attacks that lead to a fault. Security in distributed MCSs was barely addressed by now. This work proposes the extension of the core services of a distributed MCSs by secure communication services.