On the Composability of Statistically Secure Random Oblivious Transfer

TL;DR

This paper proves that certain statistically secure oblivious transfer protocols are universally composable, enabling their safe use in complex cryptographic applications without compromising security.

Contribution

It establishes the universal composability of stand-alone statistically secure oblivious transfer protocols based on two-party stateless primitives.

Findings

Protocols are statistically universally composable

Previous non-composable protocols are secure in arbitrary applications

Enhances the security guarantees of existing oblivious transfer protocols

Abstract

We show that stand-alone statistically secure random oblivious transfer protocols based on two-party stateless primitives are statistically universally composable. I.e. they are simulatable secure with an unlimited adversary, an unlimited simulator and an unlimited environment machine. Our result implies that several previous oblivious transfer protocols in the literature which were proven secure under weaker, non-composable definitions of security can actually be used in arbitrary statistically secure applications without lowering the security.