Mobile phone applications can be great for a range of different everyday purposes. However, most users are unaware of what the apps are doing while they are unattended. In his research, Ph.D. candidate Nurul Momen has investigated how apps behave, and how they use the personal data users authorise them to access. In our conversation, Nurul describes the dangers of personal data craving apps, and he explains how his research can help increasing transparency and protect user privacy. Nurul Momen’s licentiate thesis can be retrieved from DiVA: Towards Measuring Apps’ Privacy-Friendliness