Many studies of mobile security and privacy are, for simplicity, limited to either only Android users or only iOS users. However, it is not clear whether there are systematic differences in the privacy and security knowledge or preferences of users who select these two platforms. Understanding these differences could provide important context about the generalizability of research results. This paper reports on a survey (n=493) with a demographically diverse sample of U.S. Android and iOS users. We compare users of these platforms using validated privacy and security scales (IUIPC-8 and SA-6) as well as previously deployed attitudinal and knowledge questions from the Pew Research Center. As a secondary analysis, we also investigate potential differences among users of different smart-speaker platforms, including Amazon Echo and Google Home. We find no significant differences in privacy attitudes of different platform users, but we do find that Android users have more technology knowledge than iOS users. In addition, we find evidence (via comparison with Pew data) that Prolific participants have more technology knowledge than the general U.S. population.
