Secure spontaneous device association

One of the principal requirements of ubiquitous computing is support for spontaneous interoperation, in which two or more devices interact temporarily in ad hoc circumstances. Spontaneity typically arises when nomadic users carry one or more of the devices around. We contribute a method of using lasers for securing spontaneous device associations. The method provides users with physical evidence of which device they have connected their device to, as well as setting up a secure channel between the devices.