Research And Applications Of Practical Functional Encryption Scheme

Functional encryption is an extension of the traditional encryption,which allows a third party to compute and output the function of the plaintext without decrypting the ciphertext,making it ideal for cryptographic data outsourcing scenarios.Functional encryption is an important branch of modern cryptography,which has important theoretical value and wide application prospect.However,currently,all of general functional encryption schemes that support arbitrary functions use inefficient indistinguishable obfuscators,so it is not yet practical.In this paper,we will focus on the specific and practical functional encryption scheme,such as inner product encryption,order-revealing encryption(ORE).These specific functions are the special cases of the general functions,and their construction does not depend on the indistinguishable obfuscator,therefore they are very efficient.Our main research results are as follows:1.Kim et al.described three applications of function-hiding inner product: the encrypted biometric authentication,the encrypted nearest neighbor search,and the encrypted linear regression.However,they did not implement the programs.Our main contributions are as follows: these three applications are described in details,and the programs are implemented.2.Lewi et.al proposed a range query scheme over encrypted data scheme based on ORE.Their scheme uses the liner list to organize the data,and use the binary search algorithm.While the time complexity of the algorithm is logarithmic,it is necessary to move a large amount of data when insert and delete them,leading to a lot of unnecessary overhead.In this paper,we use B+ tree data structure to organize data.In comparison,the time complexity of our improved scheme is logarithmic when search,insert and delete data.