Smart wearable devices have enormous applications in today's world and hence their usage is increasing significantly. As these devices communicate using wireless medium, the communication must be protected from eavesdropping by using shared secret keys for data encryption. In many applications, it is essential to use a common secret key for secured communication among multiple devices. In this paper, we present our novel secret key generation and distribution protocol exploiting accelerometer data collected from smart wearable devices. We propose (i) source separation method for processing accelerometer sensor data, and (ii) key distribution protocol based on Fuzzy vault. Our scheme is information theoretically secure and our experimental results show that the maximum key generation rate of our scheme is 50 bps which is suitable for practical applications.