CROOT: Code-based Round-Optimal Oblivious Transfer

Nicolas Aragon, Olivier Blazy, Neals Fournaise, Philippe Gaborit


In this paper, we present a new functionality for 1-out-of-2 Oblivious Transfer. This functionality lives between the classical and the weak-Oblivious Transfer ones. We motivate this functionality to adapt and prove a formerly proposed (and retracted) framework that was shown to be unprovable with the classical OT functionality. Our functionality still remains reasonably close to natural expectation for Oblivious Transfer. Once our global framework is proven in the new functionality, we propose two instantiations using recent code-based candidates of the NIST post-quantum standardization process. We show that the resulting instantiations are both efficient and secure. Our new functionality opens the way to round-optimal oblivious transfer instantiations.


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