Security in Ad-hoc and Sensor Networks

We then address cooperation between wireless nodes, and show that this problem naturally leads to the prevention of greedy behavior in WiFi hot spots; we detail our solution to this problem, called DOMINO. We then address a very novel problem, namely the secure location of a node; we explain the potential of this feature, taking the examples of the secure location of smart vehicles in road traffic and the prevention of attacks against sensor networks positions. We show how this feature can be implemented by an appropriate combination of distance bounding and multilateration.

The common perception of public key cryptography is that it is complex, slow and power hungry, and as such not at all suitable for use in ultra-low power environments like wireless sensor networks. It is therefore common practice to emulate the asymmetry of traditional public key based cryptographic services through a set of protocols [1] using symmetric key based message authentication codes (MACs). Although the low computational complexity of MACs is advantageous, the protocol layer requires time synchronization between devices on the network and a significant amount of overhead for communication and temporary storage. The requirement for a general purpose CPU to implement these protocols as well as their complexity makes them prone to vulnerabilities and practically eliminates all the advantages of using symmetric key techniques in the first place. In this paper we challenge the basic assumptions about public key cryptography in sensor networks which are based on a traditional software based approach. We propose a custom hardware assisted approach for which we claim that it makes public key cryptography feasible in such environments, provided we use the right selection of algorithms and associated parameters, careful optimization, and low-power design techniques. In order to validate our claim we present proof of concept implementations of two different algorithms—Rabin’s Scheme and NtruEncrypt—and analyze their architecture and performance according to various established metrics like power consumption, area, delay, throughput, level of security and energy per bit. Our implementation of NtruEncrypt in ASIC standard cell logic uses no more than 3,000 gates with an average power consumption of less than 20 μW. We envision that our public key core would be embedded into a light-weight sensor node architecture.

More and more, people will continuously be using ubiquitously available networked computational devices as they go about their lives: small personal devices that they carry, appliances that they find in their surroundings, and servers in remote data centers. Some of the data exchanged by these devices will be private and should be protected. Normally to protect data, users would need to authenticate themselves with a device by signing on to it. However it will be physically impossible to sign onto devices that have limited or no user interface and even if they all had a sufficient user interface it will be an intolerable burden to have to sign on to each of many devices, particularly as the membership of the ensemble of devices continuously changes with the user’s movements. Making authentication in this environment more difficult is the fact that these devices are usually connected in a personal area network that is neither secure nor reliable and uses a broadcast medium for communication. In this paper, we present a simple easy-to-use scheme that allows users to sign on to a single device and enable the rest of the devices connected in the personal area network automatically without requiring a central server or synchronized clocks. As well as being simple for the user, our solution is designed not only to prevent commonly used attacks like replay and man-in-the-middle but also to protect the user’s data even if the devices are lost or stolen.