Hi-KD: Hash-based hierarchical Key Distribution for Group Communication

Even though hierarchical group communication is a prominent communication model for a variety of applications, featured by hierarchical communication rules, it has not been sufficiently investigated in the security literature. In this paper, we introduce private hierarchical group communication and we determine its specific confidentiality requirements, then we propose an efficient key management protocol satisfying those requirements. This work is done in the frame of a national french project whose consortium includes the international telecom company EADS, INRIA, CNRS and ENST-Paris. The project is called SafeCast and deals with group communication in PMR networks that are used mainly by security corps (police, fire fighters, soldiers,. . . ) in areas where it is difficult to have network infrastructures, such as war battles or following a natural disaster (earthquake, tsunami, tornado, . . . ).