With the rapid development of embedded technology and mobile computing, we have seen a growing number of Internet of Things (IoT) devices on the market. As the number of wearable devices belonging to the same user increases rapidly, secure pairing between legitimate devices becomes an important research problem. In this chapter, we propose the first gait-based shared key generation system that assists two devices to generate a common secure key by exploiting the user’s unique walking pattern. The system is based on the fact that sensors on different positions of the same user exhibit similar accelerometer signal when the user is walking. Therefore, the acceleration can be used as a shared secret information to generate a common key on different devices independently. Our experimental results show that the key generated by two independent devices on the same body is able to achieve 100% bit agreement rate. The proposed key generation protocol can establish a 128-bit key in 5 s (about 10 steps) with entropy varying from 0.93 to 1. We also find that the proposed scheme can run in real time on modern smartphone and require low system cost.
Part of the book: Medical Internet of Things (m-IoT)