Digital signatures with classical shadows on near-term quantum computers
Quantinuum；Department of Computer Science, University of Chicago（芝加哥大学计算机科学系）
Pradeep Niroula, Minzhao Liu, Sivaprasad Omanakuttan, David Amaro, Shouvanik Chakrabarti, Soumik Ghosh, Zichang He, Yuwei Jin, Fatih Kaleoglu, Steven Kordonowy,… 展开作者
Pradeep Niroula, Minzhao Liu, Sivaprasad Omanakuttan, David Amaro, Shouvanik Chakrabarti, Soumik Ghosh, Zichang He, Yuwei Jin, Fatih Kaleoglu, Steven Kordonowy, Rohan Kumar, Michael A. Perlin, Akshay Seshadri, Matthew Steinberg, Joseph Sullivan, Jacob Watkins, Henry Yuen, Ruslan Shaydulin
Quantum mechanics provides cryptographic primitives whose security is grounded in hardness assumptions independent of those underlying classical cryptography. However, existing proposals require low-noise quantum communication and long-lived quantum memory, capabilities which remain challenging to realize in practice. In this work, we introduce a quantum digital signature scheme that operates with only classical communication, using the classical shadows of states produced by random circuits as public keys. We provide theoretical and numerical evidence supporting the conjectured hardness of learning the private key (the circuit) from the public key (the shadow). A key technical ingredient enabling our scheme is an improved state-certification primitive that achieves higher noise tolerance and lower sample complexity than prior methods. We realize this certification by designing a high-rate error-detecting code tailored to our random-circuit ensemble and experimentally generating shadows for 32-qubit states using circuits with $\geq 80$ logical ($\geq 582$ physical) two-qubit gates, attaining 0.90 $\pm$ 0.01 fidelity. With increased number of measurement samples, our hardware-demonstrated primitives realize a proof-of-principle quantum digital signature, demonstrating the near-term feasibility of our scheme.
量子糖果（Quantum candies，简称Qandies）是一种教学用的简单模型，它直观地描述了量子信息处理（quantum information processing，简称QIP）中的许多概念，不需要理解或利用叠加，也不需要使用复杂的代数。近年来，量子密码学的一个研究热点是量子数字签名（QDS），涉及使用量子方法安全地签署经典位的协议。在本文中，我们展示了如何“Qandy模型”可以用来描述三个QDS协议，以提供一个重要的和潜在的实际例子的权力“无叠加”的量子信息处理，个人没有背景知识的领域。
Experimental transmission of quantum digital signatures over 90-km of installed optical fiber using a differential phase shift quantum key distribution system
Realization of Quantum Digital Signatures without the requirement of quantum memory
数字签名被广泛用于为电子通信提供安全性，例如在金融交易和电子邮件中。然而，目前使用的经典数字签名方案仅提供依赖于未经证明的计算假设的安全性。相比之下，量子数字签名（QDS）提供基于量子力学定律的信息理论安全性（例如Gottesman和Chuang 2001）。在这里，防止伪造的安全性依赖于不可能完全区分非正交的量子态。然而，以前的QDS方案的一个严重缺点是它们需要长期的量子存储器，这使得它们在实践中不可行。我们提出了一个方案的第一个实现（Dunjko et al 2013），它不需要量子存储器，并且只使用标准的线性光学元件和光电探测器。为了实现这一点，接收者使用新型的量子测量、量子态消除来测量分布式量子签名状态（例如，Barnett 2009，Bandyopadhyay等人2013）。这大大推进了QDS作为一种具有实际应用潜力的量子技术。
