Biometric identification in context-based applications is a promising research area.However, several legal issues should be taken into account when developing context-based applications conforming to legal notions like privacy, human rights, etc. In this paper, we present a guide to the social guarantees to be built into context-based systems for private relations (between private user and private services) and public relations (between private/public users and public services). The proposal in this paper focuses on a set of goals that context-based applications should achieve to guarantee privacy and human rights.