Flexible rigidity: Compiling generic trusted-preparation protocols into sequential device-independent
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Today
- LecturerDr. Srijita Kundu (Hon Hai Research Institute, Quantum Computing Research Center (QCRC))
Host: Kai-Min Chung - Time2026-11-04 (Wed.) 10:15 ~ 12:15
- LocationAuditorium 101 at IIS new Building
Abstract
In this work, we give a generic compiler for turning a wide class of device-dependent protocols with trusted state preparation into sequential device-independent protocols. In order for our compiler to apply, the trusted-preparation protocol needs to satisfy certain minimal conditions: having an entanglement-based realization in the first place, and the entanglement-based realization corresponding to the optimal strategy of any non-local game that satisfies a fairly weak rigidity condition. We apply our generic compiler to give sequential device-independent protocols for uncloneable encryption, copy-protection of point functions, and blind randomness expansion.
Our technical contribution is a new class of rigidity theorems based on Renyi divergences, with flexible cryptographic applications. They allow our compiler to achieve a constant rate (i.e., the ratio of trusted states prepared to device uses) arbitrarily close to 1/2, while tolerating a constant level of noise per device usage. This overcomes a fundamental scaling obstacle faced by previous rigidity theorems for trace distance or fidelity.
Based on joint work with Amir Arqand and Ernest Tan. arXiv: https://arxiv.org/abs/2610.00444