The Research Of(m+1,t+1) Threshold Secret Sharing Based On Cloud Computing

Cloud computing is user-oriented and has characters of high dynamic and reliability,which can allocate resources reasonably.In the cloud computing platform,user's privacy data stored in the cloud server are kept by cloud service providers.The security of user's privacy data is facing potential threat from untrusted cloud service providers.Cloud service providers may reveal even steal user's private data for some reasons.In this thesis,a(m+1,t+1)threshold secret sharing scheme based on cloud computing is proposed to prevent untrasted cloud service providers from stealing user's privacy data by encrypting user's privacy data and managing decryption key effectively.Finished works in this thesis are as follows:(1)Research background,significance of this thesis,present situation on cloud computing storing security and threshold secret sharing are introduced.Several classic threshold secret sharing schemes and threshold secret sharing schemes based on special privileges are discussed.(2)To solve the problem that untrusted cloud service providers steal user's privacy data,in the cloud computing platform,a(m+1,t+1)threshold secret sharing scheme based on homogeneous linear difference equations with constant coefficients is put forward.This scheme distributes a special secret share for user and produces common secret shares to cloud service providers according to homogeneous linear difference equations with constant coefficients.A user and t cloud service providers can recover decryption key,but any m-1 cloud service providers or fewer of them can't recover the decryption key without user's participation.(3)The security and robustness of the scheme are analyzed from three aspects of collusion-resisted,cheating prevention and tolerance of share loss.The analysis shows that the proposed scheme not only solves the problem that untrusted cloud service providers steal user's privacy data but also has better robustness.(4)An example is used to verify the correctness of this scheme.Under Windows 8 operating system,a cloud security storage prototype system based on(m+1,t+1)threshold is designed and exploited by using VC++ 6.0,which verify the effectiverness and feasibility of the scheme.