Information is becoming a crucial if not the most important resource of the economy and the society at large. Information differs radically from other resources; for instance, it can be copied without cost, it can be communicated at the speed of light, and it can be destroyed without leaving traces. This poses new challenges for the protection of this new resource and of intellectual property in general. Information security, in particular cryptography, is an enabling technology that is vital for the development of the information society. Information Security for protecting information in potentially hostile environments is a crucial factor in the growth of information-based processes in industry, business, and administration. Cryptography is a key technology for achieving information security in communications, computer systems, electronic commerce, and in the emerging information society. After peer review, the guest editors accepted 25 final accepted papers from 102 online submissions for the special issue to reflect the current development of information security and cryptology technology.

   The first paper by Dongsheng Ning, Xiaoyan Xu, Yanping Yu, Xinxin Liu and Xiaoyan Wang is entitled “UWB-based Receiver Initiated MAC Protocol with Packet Aggregation and Selective Retransmission”. The authors proposes a UWB-based MAC protocol for wireless multimedia networks named as UWB-based Receiver initiated MAC protocol with Packet aggregation and Selective retransmission (URMPS), which can reduce long acquisition time and large overhead, and support more concurrent transmissions. The receiver initiated request, packet aggregation and selective retransmission are used to reduce synchronization acquisition time and overhead. The combination of mutually exclusive area and time-hopping (TH) code is to mitigate the interference caused by concurrent transmissions of multiple nodes. The simulation results run over NS-2 show that URMPS protocol performs better in terms of network throughput and delay compared to S-MAC.

   The second paper by Ting Han, Shoushan Luo, Hongliang Zhu, Yang Xin and Yong Peng is entitled “A Novel Trust Evaluation Model Based on Gray Clustering Theory for Routing Networks”. In this paper, by learning trust relationship from routing network, a trust evaluation model based on Grey Clustering Theory is proposed. The model adopts improved Bayes theory to evaluate the behavior trust. By introducing Grey Clustering Theory, the model clusters the recommend node to different trust classes according to recommend credibility and calculates the recommend weight to resistance the fraud recommends information from the deceptive node. Simulation results show that trust evaluation model based on Grey Clustering Theory cannot only effectively evaluate the routing node behavior but also has better anti-attack performance, anti-deception performance and higher attack node detection rate.

   The third paper by Wentao Cui, Kai Niu, Qian Wan, Weiling Wu is entitled “A Robust and Efficient Clustering Algorithm for Network MIMO System”. The authors propose a heuristic algorithm to dynamically bind together some base stations, which can adjust itself to the ever-changing interference condition. Through utilizing the predefined connection graph, the complexity of proposed scheme is reduced while retaining a similar performance to exhaustive searching algorithm. Compared with other previous clustering methods, the proposed one demonstrates its robustness against the unrealistic feedback channel and mostly matches the performance gain produced by exhaustive searching clustering strategy.
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