Active spaces and smart rooms are quickly gaining popularity in both the research arena, and in commercial projects. Active spaces are physical spaces populated with massive numbers of specialized embedded computing devices that increase human productivity by enabling users to interact seamlessly with the surrounding environment. Security for active spaces is necessary. In such settings, it is essential to have lightweight, mobile and convenient security services for users that enable them to prove their identities and interact securely with the smart devices that populate the surrounding environment. We propose embedding the security services in a basic wearable device that is already being worn and used by many people on daily basis, the wristwatch. We describe our implementation of these wearable security services, and show how the system is used in our active space test-bed.