An Empirical Study on Android for Saving Non-shared Data on Public Storage

With millions of apps provided from official and third-party markets, Android has become one of the most active mobile platforms in recent years. These apps facilitate people’s lives in a broad spectrum of ways but at the same time touch numerous users’ information, raising huge privacy concerns. To prevent leaks of sensitive information, especially from legitimate apps to malicious ones, developers are encouraged to store users’ sensitive data into private folders which are isolated and securely protected. But for non-sensitive data, there is no specific guideline on how to manage them, and in many cases, they are simply stored on public storage which lacks fine-grained access control and is almost open to all apps.