Welcome to D-SPAN 2013, the Fourth IEEE International Workshop on Data Security and PrivAcy in wireless Networks (D-SPAN). The workshop focuses on research developments related to data security and privacy in wireless and mobile networks. This workshop solicits papers from two main categories: (1) papers that consider the security and privacy of data collection, transmission, storage, publishing, and sharing in wireless networks broadly defined, e.g., MANET, cellular, vehicular, ad hoc, cognitive, and sensor networks; and (2) papers that use data analytics to address security and privacy problems in wireless networks. The workshop provides a venue for researchers to present new ideas with impact on three communities – wireless networks, databases, and security.