Efficient high rate secret key extraction in sensor networks using collaboration

poste

Secret key extraction using Bluetooth wireless signal strength measurements

pre-printBluetooth has found widespread adoption in phones, wireless headsets, stethoscopes, glucose monitors, and oximeters for communication of, at times, very critical information. However, the link keys and encryption keys in Bluetooth are ultimately generated from a short 4 digit PIN, which can be cracked off-line. We develop an alternative for secure communication between Bluetooth devices using the symmetric wireless channel characteristics. Existing approaches to secret key extraction primarily use measurements from a fixed, single channel (e.g., a 20 MHzWiFi channel); however in the presence of heavy WiFi traffic, the packet exchange rate in such approaches can reduce as much as 200. We build and evaluate a new method, which is robust to heavy WiFi traffic, using a very wide bandwidth (B 20 MHz) in conjunction with random frequency hopping. We implement our secret key extraction on two Google Nexus One smartphones and conduct numerous experiments in indoor-hallway and outdoor settings. Using extensive real-world measurements, we show that outdoor settings are best suited for secret key extraction using Bluetooth. We also show that even in the absence of heavy WiFi traffic, the performance of secret key generation using Bluetooth is comparable to that of WiFi while using much lower transmit power

Secure key design approaches using entropy harvesting in wireless sensor network: A survey

Physical layer based security design in wireless sensor networks have gained much importance since the past decade. The various constraints associated with such networks coupled with other factors such as their deployment mainly in remote areas, nature of communication etc. are responsible for development of research works where the focus is secured key generation, extraction, and sharing. Keeping the importance of such works in mind, this survey is undertaken that provides a vivid description of the different mechanisms adopted for securely generating the key as well its randomness extraction and also sharing. This survey work not only concentrates on the more common methods, like received signal strength based but also goes on to describe other uncommon strategies such as accelerometer based. We first discuss the three fundamental steps viz. randomness extraction, key generation and sharing and their importance in physical layer based security design. We then review existing secure key generation, extraction, and sharing mechanisms and also discuss their pros and cons. In addition, we present a comprehensive comparative study of the recent advancements in secure key generation, sharing, and randomness extraction approaches on the basis of adversary, secret bit generation rate, energy efficiency etc. Finally, the survey wraps up with some promising future research directions in this area

Doctor of Philosophy

dissertationCross layer system design represents a paradigm shift that breaks the traditional layer-boundaries in a network stack to enhance a wireless network in a number of di erent ways. Existing work has used the cross layer approach to optimize a wireless network in terms of packet scheduling, error correction, multimedia quality, power consumption, selection of modulation/coding and user experience, etc. We explore the use of new cross layer opportunities to achieve secrecy and e ciency of data transmission in wireless networks. In the rst part of this dissertation, we build secret key establishment methods for private communication between wireless devices using the spatio-temporal variations of symmetric-wireless channel measurements. We evaluate our methods on a variety of wireless devices, including laptops, telosB sensor nodes, and Android smartphones, with diverse wireless capabilities. We perform extensive measurements in real-world environments and show that our methods generate high entropy secret bits at a signi cantly faster rate in comparison to existing approaches. While the rst part of this dissertation focuses on achieving secrecy in wireless networks, the second part of this dissertation examines the use of special pulse shaping lters of the lterbank multicarrier (FBMC) physical layer in reliably transmitting data packets at a very high rate. We rst analyze the mutual interference power across subcarriers used by di erent transmitters. Next, to understand the impact of FBMC beyond the physical layer, we devise a distributed and adaptive medium access control protocol that coordinates data packet tra c among the di erent nodes in the network in a best e ort manner. Using extensive simulations, we show that FBMC consistently achieves an order-of-magnitude performance improvement over orthogonal frequency division multiplexing (OFDM) in several aspects, including packet transmission delays, channel access delays, and e ective data transmission rate available to each node in static indoor settings as well as in vehicular networks