International Association for Cryptologic Research

International Association
for Cryptologic Research


Tang Xueming


A Framework For Fully-Simulatable $h$-Out-Of-$n$ Oblivious Transfer
Zeng Bing Tang Xueming Chingfang Hsu
In this paper, we present a framework for efficient, fully-simulatable $h$-out-of-$n$ oblivious transfer ($OT^{n}_{h}$) with security against nonadaptive malicious adversary. The number of communication round of the framework is six. Compared with existing fully-simulatable $OT^{n}_{h}$, our framework is round-efficient. Conditioning on no trusted common string is available, our DDH-based instantiation is the most efficient protocol for $OT^{n}_{h}$. Our framework uses three abstract tools, i.e. perfectly binding commitment, perfectly hiding commitment and our new smooth projective hash. This allows a simple and intuitive understanding of its security. We instantiate the new smooth projective hash under the lattice, decisional Diffie-Hellman, decisional N-th residuosity, decisional quadratic residuosity assumptions. This indeed shows that the folklore that it is technically difficult to instantiate the projective hash framework under the lattice assumption is not true. What's more, by using this lattice-based instantiation and Brassard's commitment scheme, we gain a $OT^{n}_{h}$ instantiation which is secure against any quantum algorithm.


Zeng Bing (1)
Chingfang Hsu (1)