Secure localized storage based on super-distributed RFID-tag infrastructures Marc Langheinrich Institute for Pervasive Computing, ETH Zurich, Switzerland, langhein@inf.ethz.ch Abstract Humans are social creatures that often take pleasure in sharing ideas and opinions with others. While the Internet has made this process much easier (Wikipedia, Flickr, Facebook), it has also made the assembly of such shared information into central profiles with the help of a simple online search dangerously trivial. Access control could of course be used to prevent this, yet this would also limit the sharing of such information to a much smaller set of well-known users, as well as introducing a significant administrative overhead. This paper presents FragDB, a storage concept based on localized access control, where data storage and retrieval are bound to a specific place, rather than the knowledge of a particular password or certificate. Data shared using FragDB is much harder to assemble into a profile, as a person’s activities across space and time are not centrally assembled, but require actual physical presence for querying. FragDB uses the IDs of tiny RFID tags embedded in floors, walls, or doors, to compute a local key that is used to encrypt and decrypt data in a global storage system. It is particularly suited to disseminate information pertaining to a particular location or a local group. We describe the requirements and implementation of such a system, and analyze its complexity.