The document presents the PEPERS project which aims to develop an infrastructure to support designing secure mobile peer-to-peer (P2P) applications. It discusses the challenges of security in mobile P2P systems and introduces the PEPERS Development Methodology (PDM), a 5-stage methodology supported by tools to help developers build secure mobile P2P apps. It also describes case studies and evaluations that demonstrate the benefits of the PDM approach while identifying opportunities for further improvements.