Secure oblivious transfer protocol from indistinguishability obfuscation

Yuan, Zheng Zheng, Wang +3 more

Shanshan Zhang

Mei Wang, Zheng Yuan, Feng Xiao

We proposed a new secure oblivious transfer protocol from indistinguishability obfuscation in this paper. Our main technical tool is the candidate indistinguishability obfuscation introduced in [1] and a dual-mode cryptosystem proposed in [2]. Following their steps, we presents a new k-out-of-l oblivious transfer protocol, its realization from DDH is described in this paper, in which we combined indistinguishability obfuscation with the dual-mode cryptosystem. The security of our scheme mainly relies on the indistinguishability of the obf-branches ( corresponding to the two modes in dual-mode model). Our paper explores a new way for the application of indistinguishability obfuscation.

Michael J. Fischer, Silvio M. Micali, Charles Rackoff

Richard J. Berger, René Peralta, Tom Tedrick

LI Xiaodong, ZHU Xiaopeng, ZHANG Jianyi, WU Yong, DOU Yimeng

The Oblivious Transfer (OT) protocol is a privacy-preserving two-way communication protocol important for building secure multiparty computations. To exchange symmetric keys, this protocol is typically based on the Rivest—Shamir—Adleman (RSA) or Diffie—Hellman (DH) cryptographic systems, which are used for encryption during the message-encryption phase. However, in existing OT protocols, the generation of multiple pairs of public and private keys and data computations are time-consuming. Using bijective functions to transform the ciphertext within the same ciphertext domain can ensure indistinguishability after decryption and reduce the computational complexity. In the semi-honest model, a ciphertext obfuscation-based OT protocol framework is proposed and OT protocols are instantiated based on RSA and DH within this framework. Compared with RSA-based encryption schemes, the proposed protocol requires only one pair of public and private keys. When the number of public and private keys is reduced to one, the receiver can use the public key in the digital certificate of the sender to implement the OT protocol using an identity authentication function. Compared with the OT protocol based on the DH key exchange, this protocol has a small data transmission volume and low computational complexity. Experimental results show that, compared with existing OT protocols, the efficiency of instantiated protocols in the key exchange stage can be improved by at least 30%. Moreover, this protocol can be used as a basic protocol for privacy set intersections, obfuscation circuits, and OT extension protocols.