Oblivious Transfer Protocol Based On Public Key Scheme

Oblivious transfer(OT) protocol is one of the most fundamental cryp-tographic protocols, showing its great value in proposing secure multi-party computation, meanwhile, it takes an important role in the area of E-vote, E-contracts, Information Retrial, and so on. So, it has brought on great researches on how to propose an secure OT protocol since it has been in-troduced. Most of OT protocols in the past few decades were set up in stand-alone model, their security are directly based on the hardness of math-ematical problems or computational problems, however, it is a challenging task to design secure OT protocols in open, multi-protocol, multi-party ex-ecution environments. These years, the relationships between OT protocol and Public Key primitives have motivated to construct OT protocol from them. and this method shows great advantages in security and efficiency. It is proved that, there exist black-box reductions between OT protocol and public key encryption(PKE), key agreement(KA), One-Way functions, and so on, such as, k-OT imply k-KA, PKE with special properties imply OT. And in practical, OT protocols built from KA, Blind Signature, and Thresh-old Encryption have present in recent years.Main work in this paper are summarized as following:1) Present a delicate introduction of OT protocol, including the defini-tion and security of it. and present a list of classical OT protocols. After analyzing the simulation-based secure OT protocol, we formalize the secu-rity and proof of OT protocol.2) By means of the logic of black-box reductions, we present the known relationships between OT and PKE, KA in the means of reduction. During this process, we give some analysis on the possibility of other public key primitives to build OT protocol. 3) Illustrate the OT protocol proposed by Dahlia, et. Dahlia's proposal is the first OT protocol that built from blind signature. alongside their method, we build a new OT protocol based on blind GDH signature, and we prove that our proposal is secure according with the half-simulation paradigm.4) Build a new OT protocol from threshold encryption. Based on the research that, threshold encryption has the same function to protect the receiver's security in OT protocol, we modify the blind signature used in OT protocol with (2,2)-RSA encryption and get a new OT protocol which realize one-out-of n transfer.