Abstract
Decentralized approaches for online social networks (OSNs) have been of recent research interest, enabling users to create profiles and share data like in other OSNs as, e.g., Facebook. Since the decentralized architecture does not contain a central authority that is able perform access control, encryption is needed to ensure the confidentiality of published data. This paper outlines strict requirements and weak constraints for the encryption of data attributes in decentralized OSNs. Subsequently, an overview of possible cryptographic solutions is given and their suitability according to these requirements is analyzed. As a result, the differences and trade-offs between and within the given approaches are expounded. The outcome of this paper can be used as a foundation for further investigations on this topic.