Ubiquitous computing describes the notion that computing devices will be everywhere: clothing, walls and floors of buildings, cars, farms etc. Ubiquitous computing is becoming reality. The most prominent examples of this trend are radio frequency identification devices (RFIDs) and wireless distributed sensor networks. RFIDs are currently being introduced into the supply chain. Wireless sensor networks (WSN) are in use to monitor wildlife and to track military targets. Many more applications are being envisioned. Ubiquitous computing devices are being built into the fabric of our infrastructure. Security is a critical factor for these devices due to their impact on privacy, trust and control.
In order to provide security we have to design and built cryptographic algorithms that are specifically tailored to the needs of the applications of ultra-low power devices and that can function within their very constraint environment.
The security of almost all cryptographic systems depends on the randomness, unpredictability and secrecy of the key. Many cryptographic protocols require random numbers also for purposes other than the key. Therefore a true random number generator (TRNG) must meet stringent requirements. Designing TRNGs is the subject of current research and most published implementations have large hardware requirements. It is especially challenging to build a TRNG within the constraints of ultra-low power applications.
This topic covers the physical security of the devices as well as side channel attacks. Many applications of wireless sensor nodes and RFID tags makes them vulnerable to attacks. The physical implementation of cryptographic algorithms can leak information about secret data to an attacker through side channels e.g., fluctuation in power consumption, electro magnetic radiation, etc. Techniques to thwart these attacks are currently being developed and require substantial amounts of additional hardware. However, it might be possible to apply some of these known techniques to ultra-low power devices.