Stronger leakage, measurement, reusability, and composition guarantees for device-independent protocols

Achieve a constant leakage rate, constant fault tolerance under arbitrary joint measurements, reusable device batches, and concurrent composition for device-independent oblivious transfer and bit commitment protocols based on post-quantum one-way functions.

Background

The paper constructs device-independent oblivious transfer and bit commitment from post-quantum one-way functions in two regimes. The isolated regime supports constant honest-device fault tolerance but assumes zero inter-laboratory leakage and coordinate-local measurements by the honest receiver. The general regime permits bounded adaptive leakage and arbitrary joint measurements, but its fault tolerance is only inverse-polylogarithmic, and each invocation requires a fresh, isolated device batch.

The authors identify four unresolved extensions of the present guarantees: allowing leakage at a constant rate rather than only a polylogarithmic total per batch; retaining constant fault tolerance when honest measurements are arbitrary joint measurements; reusing device batches instead of retiring them after a single invocation; and obtaining concurrent rather than merely sequential composition. The sentence explicitly characterizes all four as remaining open, while noting that they may reflect limitations of the analysis rather than inherent limitations of the approach.