SPA: Inviting Your Friends to Help Set Android Apps

More and more powerful personal smart devices take users, especially the elder, into a disaster of policy administration where users are forced to set personal management policies in these devices. Considering a real case of this issue in the Android security, it is hard for users, even some programmers, to generally identify malicious permission requests when they install a third-party application. Motivated by the popularity of mutual assistance among friends (including family members) in the real world, we propose a novel framework for policy administration, referring to Socialized Policy Administration (SPA for short), to help users manage the policies in widely deployed personal devices. SPA leverages a basic idea that a user may invite his or her friends to help set the applications. Especially, when the size of invited friends increases, the setting result can be more resilient to a few malicious or unprofessional friends. We define the security properties of SPA, and propose an enforcement framework where users' friends can help users set applications without the leakage of friends' preferences with the supports of a privacy preserving mechanism. In our prototype, we only leverage partially homomorphic encryption cryptosystems to implement our framework, because the fully homomorphic encryption is not acceptable to be deployed in a practical service at the moment. Based on our prototype and performance evaluation, SPA is promising to support major types of policies in current popular applications with acceptable performance.