We quickly approach a "pervasive future" where pervasive computing is the norm. In this scenario, humans are surrounded by a multitude of heterogeneous devices that assist them in almost every aspect of their daily routines. The realization of this future demands strong authentication guarantees to ensure that these devices are not abused and that their users are not endangered. However, providing authentication for these systems is a challenging task due to the high heterogeneity of pervasive computing applications. This heterogeneity makes it unfeasible to propose a single authentication solution for all of the pervasive computing applications. In this paper, we review several pervasive application scenarios and promising authentication methods for each. To do this, we first identify the key characteristics of each pervasive application scenario. Then, we review the strengths and weaknesses of prominent authentication methods from the literature. Finally, we identify which authentication methods are well suited for each application scenario based on the identified characteristics. Our goal is to provide promising directions to be explored for authentication in each of these scenarios.