Military secure communications over public cellular network infrastructure

The availability of a tactical communication channel that could be everywhere accessible possibly via wireless devices and provide an adequate bandwidth is a constant matter for both military and law enforcement agencies. In particular, the public cellular network infrastructure can provide with such features. However, while conducting military operations, resorting to such a network is not a viable solution, usually,for two main reasons: (1) the host country does not provide a cellular network infrastructure (e.g. Somalia); (2) public cellular network infrastructure does not natively provide a satisfactory level of security. However, the 21st century scenario is offering quite different challenges: peacekeeping and peace enforcing military operations are deployed in a wide area require communications resources in an unprecedented manner. Moreover, these operations are being deployed in well-developed countries, where the public cellular network infrastructure is mainly available. However, the level of security of this media is still very low. The opportunities offered by this new scenario, as for the communication framework, have primarily to face security concerns, and secondarily, bandwidth requirements. Current solutions address such points only resorting to the military communications (MilCom) carrier to assure security (e.g. SatCom). However, since communications resources are, limited with respect to needs, some sort of bandwidth sharing is imposed to users, thus introducing delays. In this paper, leveraging the prospected new scenario, we describe an alternative solution to address both security and bandwidth requirements. In particular, we propose to adopt the available hosting country public cellular GSM network within a defined framework of security. The solution proposed is aimed at using the IPSec suite to guarantee the desired level of security. Migrating communication from reserved, constrained military channel, to secured public network infrastructure, has another main advantage: it allows one to unload the secure military channel from routinely or low privileged traffic, increasing the availability and the bandwidth that can be dedicated to high level, high priority traffic. Our proposal has been tested on a physical GSM based cellular network: results indicate that the overhead necessary to reach a satisfactory level of security tuning the IPSec parameters is reasonably small.