Fault Tolerant Key Generation and Secure Spread Spectrum Communication

A fundamental characteristic of wireless communications is in its broadcast nature, which allows accessibility of information without placing restrictions on a user's location. However, accessibility also makes wireless communications vulnerable to eavesdropping. In this context, this paper presents a two-part secure information transmission system. The first part makes use of reciprocity in wireless channels to allow for two asynchronous transceivers to obtain a pair of similar keys. Moreover, a unique augmentation, called strongest path cancellation (SPC), is applied to the keys. In the second part, the concept of artificial noise is introduced to the spread spectrum systems. Keys generated in the first part are used in the spread spectrum system and artificial noise is added to enhance the security of the communications. Two attacks on the proposed security solution are evaluated. First, an adversary following the same steps as the legitimate users is considered. Here, simulation and experimentation results show that SPC provides a boost to security against this type of adversary. The second attack studies an adversary with significant blind detection capabilities. Our observations on this attack indicate that when an ample amount of artificial noise can be used, two legitimate parties can communicate multiple information symbols per key.