Social network has extended its popularity from the Internet to mobile domain. Pervasive social networking (PSN) supports instant social activities based on self-organized mobile ad hoc networks. PSN is useful in reality when fixed networks are unavailable or inconvenient to access or when people are in vicinity. For supporting crucial PSN activities and enhancing user privacy, securing pervasive social communications becomes important. However, a solution based on a centralized server could be inapplicable in some specific situations (e.g., disasters and military activities) and suffers from DoS/DDoS attacks and internal attacks. How to automatically control data access in a trustworthy and efficient way in PSN is a challenge. In this paper, we propose two schemes to secure communication data in PSN purely based on local trust evaluated by PSN nodes in a distributed manner. Each node can control its data based on its trust in other nodes by applying attribute-based encryption. The advantages, security, and performance of the proposed scheme are evaluated and justified through serious analysis and implementation. The results show the efficiency and effectiveness of the schemes. In addition, we developed a mobile app based on Android platform to demonstrate the applicability and social acceptance of our schemes.