A management scheme of user private keys in an IBE system

The management of user private key in identity based encryption (IBE) system is a centralized management mode. The master key generated by PKG participates the generation of all user private keys. With the increase of users, the security problems that the user private key generation, storage and distribution faced become more and more outstanding. The paper puts forward a management method of user private key, which will divides all users into different domains according to user´s different attribute so as to reduce the uncontrollability of user private key management. While introducing the trusted third party which is responsible for user authentication, lightens the burden of servers which store user private keys. And the different domains can be communicated through establishing trust chain between domains. Finally, the paper proposes the security analysis of the scheme and which can improve the availability and security of user private key in the IBE.