This paper studies the secrecy performance in a 3-D diffusive molecular communication system with the general depleted molecule shift keying (D-MoSK) modulation, where a point transmitter Alice transmits through diffusion multiple types of molecules modulation to a legitimate absorbing receiver Bob, suffering the eavesdropping from an absorbing eavesdropper Eve. We first develop a solid theoretical framework to determine the probabilistic distributions for the number of molecules absorbed by Bob and Eve, respectively. Based on the results, we then derive the average symbol error rate (SER) as well as the mutual information of Alice-Bob and Alice-Eve, and further apply the Shannon theory to determine the secrecy capacity of Alice-Bob transmission. We also develop the closed-form results for the optimal detection threshold at Bob to achieve the secrecy capacity, and thus devise a complete algorithm for secrecy capacity maximization. Finally, we provide numerical results to illustrate the secrecy performance in the concerned system.

中文翻译：

---

基于D-MoSK的3维扩散分子通信系统的保密性能研究

本文研究了采用通用耗尽分子移位键控 (D-MoSK) 调制的 3-D 扩散分子通信系统中的保密性能，其中点发射器 Alice 通过扩散多种类型的分子调制向合法的吸收接收器 Bob 传输，一位善于倾听的窃听者伊芙的窃听。我们首先开发一个坚实的理论框架来分别确定鲍勃和夏娃吸收的分子数量的概率分布。根据结果​​，我们得出平均误码率（SER）以及Alice-Bob和Alice-Eve的互信息，并进一步应用香农理论来确定Alice-Bob传输的保密能力。我们还开发了 Bob 处最佳检测阈值的封闭形式结果，以实现保密容量，从而设计了一个用于保密容量最大化的完整算法。最后，我们提供数值结果来说明相关系统的保密性能。