Turk, Y.Tasbag, Yaman YagizZeydan, E.2023-02-152023-02-152022-08-052475-6725http://hdl.handle.net/11693/111317Real Time Mission Critical Communication (RTMCC) in emergency situations can include real-time video and audio calls between peers and first responders all occurring simultaneously. RTMCC also requires secure end-to-end (E2E) group communication (GC) sessions against potential security threats during such incidents. In this paper, we explore all aspects of the possible methods that are suitable for a software implementation of for session key change during GC in E2E encryption of RTMCC. Later, we introduce our Entropy Service concept, which can be very effective in secure E2E RTMCC sessions. The proposed method ensures E2E security in real-time communication systems while allowing very fast session key change for clients involved in an RTMCC session with a computational complexity of 𝒪(1). Our experimental results show that the proposed Entropy Service can reduce total time by 99.6% and 99.2%, the idle time by 99.4% and 98.99%, and the number of messages by 51.4% and 35.33% compared to the key refreshing and hash methods, respectively, when the number of users in the system increases to 45. These results show that both communication and computation complexity are significantly reduced with the proposed RTMCC session key change.EnglishEntropyMission criticalReal timeSecurityServiceArticle10.1002/spy2.2582475-6725