Design Of Secret Sharing Schemes And Its Application In Data Backup

Secret sharing is a very important branch of modern cryptography.It plays an important role in many applications,such as secret key management,secure multiple computing,secure authentication and so on.Secret sharing is able to divide the secret S into n shares,and the participant of qualified set can recovery the shared secret using shares.In actual applications,we need to consider the properties of multi-secret,verification,publicly verification of secret sharing and its efficiency,and its applications in different situationsIn this thesis,our aim is to improve the efficiency and character of secret sharing and its application.We proposed a efficient verifiable multi-secret sharing scheme a publicly verifiable multi-secret sharing scheme with outsourcing secret reconstruc-tion;an enhanced data backup scheme using multi-factor authentication.We have the results as follows1)Firstly,we design a novel verifiable multi-secret sharing scheme.Our scheme has more obvious advantages using linear one-way function and the modified method of Perdesen's verification.Our scheme has the following characters the participants have ability to check the validity of share;the dealer can share multi-secrets in one time,the participant of authorized set has ability to gain the secrets;the participants only keep one share and the share can be used to get different pseudo shares to recovery different secrets;having the fewer public values and updated values2)Then,we propose a publicly verifiable multi-secret sharing scheme with out-sourcing secret reconstruction.Our scheme has significant properties with the help of bilinear pairing and the cloud server.Our scheme has the following characters:multi-secrets that the dealer can share multi-secret among the set of the participants and the participants of authorized set can gain the shared secrets;privacy of the secret that the cloud server cannot gain any information about the secret,even thought the cloud server undertakes a large of computa-tion from the participants;the verification of the result that the participants of the authorized have ability to check the validity of result from the cloud server3)Finally,we design an enhanced data backup scheme using multi-factor authenti-cation.We add the random value,and use Shamir(3,2)threshold secret sharing and multi-factors authentication,and use the user's password and biometric to hide the shares for enhancing the security of scheme.Our scheme can resist the offline password attack,the user impersonation attack,and the server imper-sonation attack.Meanwhile,our scheme can update password and biometric,as well as built the session key to ensure the secure communication between the user and server.