© 2019, Springer Nature Switzerland AG. The IoT development area has drawn the attention of nowadays researchers, some of them made assumptions regarding the use of clustering in their key management schemes. For example, in CL-EKM (Certificateless Effective Key Management) protocol, cluster-heads are assumed to be with high-processing capabilities and deployed within a grid topology. In fact, this is only possible in a controlled environment. In a hostile environment, such as battlefields, this assumption cannot be satisfied. In this work, an enhancement of the CL-EKM scheme has been proposed by introducing a distributed clustering algorithm. The performance of the implemented and enhanced system proved our assumptions.