To establish secure (point-to-point and or broadcast) communication channels among the nodes of a wireless sensor network is a fundamental task. To this end, a plethora of (socalled) key pre-distribution schemes have been proposed in the past. All these schemes, however, rely on shared secret(s), which are assumed to be somehow pre-loaded onto the sensor nodes. In this paper, we propose a novel method for secure initialization of sensor nodes based on a visual out-of-band channel. Using the proposed method, the administrator of a sensor network can distribute keys onto the sensor nodes, necessary to bootstrap key pre-distribution. Our secure initialization method requires only a little extra cost, is efficient and scalable with respect to the number of sensor nodes. Moreover, based on a usability study that we conducted, the method turns out to be quite user-friendly and easy to use by naive human users.
Current mechanisms for authenticating communication between devices that share no prior context are inconvenient for ordinary users, without the assistance of a trusted authority. We present and analyze seeing-is-believing, a system that utilizes 2D barcodes and camera-telephones to implement a visual channel for authentication and demonstrative identification of devices. We apply this visual channel to several problems in computer security, including authenticated key exchange between devices that share no prior context, establishment of a trusted path for configuration of a TCG-compliant computing platform, and secure device configuration in the context of a smart home. In this paper we address the problem of secure communication and authentication in ad-hoc wireless networks. This is a difficult problem, as it involves bootstrapping trust between strangers. We present a user-friendly solution, which provides secure authentication using almost any established public-key-based key exchange protocol, as well as inexpensive hash-based alternatives. In our approach, devices exchange a limited amount of public information over a privileged side channel, which will then allow them to complete an authenticated key exchange protocol over the wireless link. Our solution does not require a public key infrastructure, is secure against passive attacks on the privileged side channel and all attacks on the wireless link, and directly captures users’ intuitions that they want to talk to a particular previously unknown device in their physical proximity. We have implemented our system in Java for a variety of different devices, communication media, and key