Paper 2016/120

Oblivious Transfer from Any Non-Trivial Elastic Noisy Channels via Secret Key Agreement

Ignacio Cascudo and Ivan Damgård and Felipe Lacerda and Samuel Ranellucci

Abstract

A $(\gamma,\delta)$-elastic channel is a binary symmetric channel between a sender and a receiver where the error rate of an honest receiver is $\delta$ while the error rate of a dishonest receiver lies within the interval $[\gamma, \delta]$. In this paper, we show that from \emph{any} non-trivial elastic channel (i.e., $0<\gamma<\delta<\frac{1}{2}$) we can implement oblivious transfer with information theoretic security. This was previously (Khurana et al., Eurocrypt 2016) only known for a subset of these parameters. Our technique relies on a new way to exploit protocols for information-theoretic key agreement from noisy channels. We also show that information theoretically secure commitments where the receiver commits follow from any non-trivial elastic channel.