Privacy-Preserving Information Sharing and Management Schema for Collaborative Social Networks by Ma Cheng Man Thesis Supervisors: Dr. Yan Zhuang Master of Science in Software Engineering Social networks have gained unprecedented popularity recently, and more social networks have emerged for specific purposes. People create information in social network. The process of information creation involves many human interactions such as tagging, selecting, and grouping. Human interacted data creation assigns abundant semantic to data. Multiple attributes have been added to data upon data creation. Some of these attributes are related to resource access control policy. A social network does not want its information open totally, therefore, each social network has to have its own resource access policy. Social network is a cyber-nation. The knowledge and information exchanged between different social networks are important in enhancing user experience. However, sharing information should not be completely barrier free as weak polices and uncontrolled sharing could lead to numerous security risks. Thus, we propose a method to effectively share information in a secure and efficient manner by establishing collaboration between social networks. The proposed method implements sharing components without changing the original data and system structure. Various social networks can be connected to each other; this connection can be referred to as a united social network (USN). Within a USN, each member social network has its own sharing policy and controls its shared information. Any two social networks can initialize communication and mutually determine sharing policies. Then, information can be shared between networks using the proposed schema. A social network user’s decisions are involved in each sharing decision. This determines access parameters. Privacy can be systematically preserved by defining subject (requester) attributes, environment attributes, and resource attributes while information is shared among different collaborative social networks.