Research On Functional Encryption Scheme And Applications

Functional encryption is a new research hotspot for public key cryptography,and it is also an extension and development of identity-based encryption,attribute-based encryption,predicate encryption and so on.Functional encryption allows the user to decrypt the partial content of the encrypted data,and this means that the user with a specific decryption key can only learn a specific function of the encrypted data.In the current cloud computing background,functional encryption has a broad prospect.We divide the functional encryption into two different kinds,one is the linear-based and the other is the lattice-based,according to different difficult problems.The current research is mainly focus on how to build functional encryption scheme which supports the general functions,how to improve the efficiency of the functional encryption scheme,and the expansion of functional encryption concept.In this paper,we work on the lattice-based scheme,and the main contribution is as follows:(1)We constructed a multi-input function encryption scheme based on LWE.At first,we introduce a functional encryption scheme based on LWE,and then we improved the basic encryption scheme and construct a simplified scheme using the Binary LWE,which means that we choose the initial vector from the Gausian Distribution,and this can reduce the complexity.And then we transform the simplified scheme into the multi-input function encryption scheme by using the NIZK proof system as well as the IO.At last,we give a simple analysis about its security.(2)We construct a searchable encryption scheme,using the multi-input function encryption scheme mentioned above,we use the comparison function to describe f,and use the Keygen process in the multi-input function encryption scheme to build the trapdoor.We achieve the multi keyword retrieving in this way.And at last we show an application of the scheme in the data sharing and the mail filter.