This book is one of the first to be dedicated entirely to the rapidly-developing field of ubiquitous computing (ubicomp). It would make an excellent introduction to the field for most people, whether they are especially interested in security or not. The first two chapters provide two very readable, bang-up-to-date and well-judged technical surveys of the current state-of-the-art in ubicomp and in computer security.
Security problems are probably the most significant obstacle to the adoption of ubiquitous computing applications. The book devotes five chapters to recent work that applies established and powerful digital security techniques to the construction of ubiquitous computing systems that offer protection against attacks on their users' privacy, identity and anonymity (which is especially important in many ubicomp applications), as well as ensuring the continuous availability of the systems to their users and the integrity of the data they use.
Much of the material in these chapters is based on work done by the author and his colleagues at Cambridge and elsewhere. The discussion is focussed by the constraints and special requirements that arise when building useful systems from computers that are worn by their users or embedded in the environment and communicate over ad-hoc wireless links. Important constraints include the need to use compact, lightweight computing devices with very low power consumption, dictating devices that have relatively low computing power and hence requiring algorithms of limited complexity in order to that conserve power.
The book is rounded off by two solid appendices with supporting material on the uses of mathematical functions and on the security of existing computer networking technologies (including the 802.11 and Bluetooth varieties of wireless network).
As in all good books on advanced technical topics, this one leads the reader into an understanding of the research problems by describing currently understood solutions in a manner that encourages the reader to consider how they might be taken further.
The author has a talent for making descriptions of quite complex technology palatable (and often even humorous) through the use of analogy, metaphor and other forms of allusions to the non-digital world. For example, there is a section titled 'The Resurrecting Duckling security policy' that explores a metaphor for the ownership of mobile devices based on Konrad Lorenz's theory of parenthood by imprinting (first demonstrated in ducklings). Another section, titled 'The Cocaine Auction Protocol' discusses a protocol for digital auctions in which anonymous bidders can participate with confidence. The author brings out the social and commercial implications of the technologies he introduces to the fore, for example by including a short discussion in the above-mentioned section on 'Do auction houses have a future?'