Oblivious Transfer from Rerandomizable PKE

Saikrishna Badrinarayanan, Daniel Masny, Pratyay Mukherjee

Bernardo David, Anderson C. A. Nascimento, Rodrigo Borges Nogueira

In this paper we propose the first code-based oblivious transfer protocol with perfect (unconditional) security for one of the parties. To obtain this result we show that the McEliece cryptosystem is rerandomizable, a property that might be of independent interest.

Bernardo David, Anderson C. A. Nascimento, Rafael Tonicelli

We introduce a general construction of fully simulatable oblivious transfer based on lossy encryption. Furthermore, we extend the common definition of lossy encryption by introducing the notion of computationally lossy encryption. If the cryptosystem used is computationally lossy, our general construction yields oblivious transfer protocols with computational security for both parties. Otherwise, when regular statistically lossy cryptosystems are employed in this construction, it yields oblivious transfer protocols with statistical security for the sender. The construction introduced in this paper is realizable from rerandomizable, homomorphic and lossy cryptosystems in general. Thus, it yields specific constructions based on different assumptions, such as DDH, LWE and McEliece. Moreover, it proves the equivalence of fully simulatable oblivious transfer and lossy encryption.

Donald Beaver

Carmit Hazay, Yehuda Lindell

Kai Chen, Qiang Yang