International Association
for Cryptologic Research

Function secret sharing(FSS) was introduced by Boyle et al. in Eurocrypt 2015, which allowed a dealer to split a secret function f into n separate pieces such that each piece enables the server who owns it to generate a secret share of the evaluation of f(x). However, when just only one collusive server returns a wrong result, reconstructing the secret will fail. Therefore, we are required to nd an applicable approach to check the correctness of result returned by the untrusted server. To solve this issue, we rstly introduce a primitive called Public Veriable Function Secret Sharing (PVFSS), and dene three new important properties: public delegation, public verication and high eciency. Then we ini- tiate a systematic study of PVFSS and construct a PVFSS scheme for point function. Not only captures our scheme these three properties, but also allows the client to verify the outcome in time constant i.e., in indeed substantially less time than performing the computation locally. We conducted a performance analysis, which manifested that our scheme can be applied into practice such as cloud/outsource computing.