Privacy preservation is of paramount importance in the emerging smart city scenario, where numerous and diverse online services will be accessed by users through their mobile or wearable devices. In this scenario, service providers or eavesdroppers can track users’ activities, location, and interactions with other users, which may discourage citizens from accessing smart city services. Pseudonym-based systems have been proposed as an efficient solution to provide identity confidentiality, and more concretely pseudonym-based signature schemes have been suggested as an effective means to authenticate entities and messages privately. In this paper we describe our implementation of a pseudonym-based signature scheme, based on bilinear-pairings. Concretely, our implementation consists of an Android application that enables users to authenticate messages under self-generated pseudonyms, while still enabling anonymity revocation by a trusted third party in case of misbehavior. The paper presents a description of the implementation, performance results, and it also describes the use cases for which it was designed.