How Dangerous Permissions are Described in Android Apps' Privacy Policies?

Google requires Android apps which handle users' personal data such as photos and contacts information to post a privacy policy which describes comprehensively how the app collects, uses and shares users' information. Unfortunately, while knowing why the app wants to access specific users' information is considered very useful, permissions screen in Android does not provide such pieces of information. Accordingly, users reported their concerns about apps requiring permissions that seem to be not related to the apps' functions. To advance toward practical solutions that can assist users in protecting their privacy, a technique to automatically discover the rationales of dangerous permissions requested by Android apps, by extracting them from apps' privacy policies, could be a great advantage. However, before being able to do so, it is important to bridge the gap between technical terms used in Android permissions and natural language terminology in privacy policies. In this paper, we recorded the terminology used in Android apps' privacy policies which describe usage of dangerous permissions. The semi-automated approach employs NLP and IE techniques to map privacy policies' terminologies to Android dangerous permissions. The mapping links 128 information types to Android dangerous permissions. This mapping produces semantic information which can then be used to extract the rationales of dangerous permissions from apps' privacy policies.