StackSync: Attribute-based data sharing in file synchronization services

摘要

Personal Cloud (PC) storage services such asDropbox or GoogleDrive have become increasinglyrnpopular in the last few years. Unfortunately, these services are still not secure. Even assumingrn“perfect” data confidentiality, securely sharing a folder in these services is still an issue, and thisrnwithout mentioning the fact that the existing sharing mechanisms are typically too coarse-grainedrnby operating at the folder level. This is insufficient in many real situations where it ismore naturalrnto grant or deny access to files based on arbitrary user attributes and selected attributes of thernfile. Inthis research,weexplore these issues and showthat fine-grained access control with strongrnprivacy guarantees is practical in the PC. To investigate the potential practicality, we took ourrnfully fledged open source implementation of a PC system and extended it to support fine-grainedrnprivate data sharing through attribute-based encryption. The result was the first design andrnimplementation of a file synchronization service, called StackSync, where the user retains completerncontrol over his or her own data when sharing it. Never before, attribute-based encryptionrnhad been implemented and tested on a real PC service. Our results show that StackSync is bothrnsecure and efficient for the PC.