Service Oriented Architectures (SOA) have been identified as a suitable mediator towards the attainment of the requirements imposed by modern warfare. Earlier studies focused primarily on the strategic domain, or the adaptation of such systems to the requirements of the tactical domain. Yet, the underlying constraints are significantly different between the two, with direct impact both on security and quality of service. In this article we approach the security aspect of tactical SOA, focusing on the specifics of the services while operating under the constrains and requirements of modern battlefields. Selected elements of our analysis within the project TACTICS are presented, as they have been utilized for the extraction of operational and technical requirements towards the development of a suitable tactical service infrastructure.