Information and communication technologies are advancing fast. Processing speed is still increasing at a high rate, followed by advances in digital storage technology, which double storage capacity every year.
Furthermore, communication techno- gies do not lag behind. The Internet has been widely used, as well as wireless te- nologies. With a few mouse clicks, people can communicate with each other around the world. All these
advances have great potential to change the way people live, introducing new concepts like ubiquitous computing and ambient intelligence. Technology is becoming present everywhere in the form of smart and sensitive c- puting
devices. They are nonintrusive, transparent and hidden in the background, but they collect, process, and share all kinds of information, including user beh- ior, in order to act in an intelligent and adaptive way. These
emerging technologies put new requirements on security and data m- agement. As data are accessible anytime anywhere, it becomes much easier to get unauthorized data access. Furthermore, the use of new technologies has brought
about some privacy concerns. It becomes simpler to collect, store, and search personal information, thereby endangering people's privacy. Therefore, research in secure data management is gaining importance, attracting the
attention of both the data management and the security research communities. The intere- ing problems range from traditional topics, such as, access control and general database security, via privacy protection to new research
directions, such as cryptographically enforced access control.