AI 中文总结
本文提出时空多方计算（MPC）概念，通过“我证明，故我在”的时空知识论证实现位置、时间等物理输入的隐私保护与一致性验证，并给出基于后量子MPC的UC安全构造。
AI 中文摘要
安全多方计算（MPC）使互不信任的各方能够在私有数字输入上进行计算。我们开创了时空多方计算的研究，将该范式扩展到其输入额外依赖于物理事实（如各方位置、时间或轨迹）的功能。此类协议必须同时隐藏时空信息并确保其物理一致性：恶意方不应能够使功能在与其实际物理状态不一致的时空输入上运行。主要的概念性挑战是在基于模拟的安全框架内阐述时空信息的提取。我们引入了时空知识论证，遵循“我证明，故我在”的原则：不直接通过数学关系定义物理存在，而是通过完成健全的时空验证协议的能力来操作性地定义它。因此，提取器从成功的证明者那里恢复一个时空点，并通过使用提取的证明者在辅助时空验证协议中成功来证明其物理有效性。基于这一概念，我们定义了时空MPC的通用可组合（UC）安全性，涵盖隐私、物理一致性和可组合性。我们提供了实现这一新MPC概念的构造。我们首先构造了时空知识的UC安全提交并证明：在CRS模型中，针对没有预共享纠缠的量子证明者，基于LWE假设；在QROM中，针对具有无界预共享纠缠的量子证明者。使用这些协议，我们从半诚实的后量子MPC获得UC安全的时空MPC。我们还将我们的框架扩展到支持具有经典时空输入的量子功能。
英文摘要
Secure multiparty computation (MPC) enables mutually distrustful parties to compute on private digital inputs. We initiate the study of spatiotemporal MPC, extending this paradigm to functionalities whose inputs additionally depend on physical facts such as the parties' locations, times, or trajectories. Such protocols must simultaneously hide spatiotemporal information and ensure its physical consistency: a malicious party should not be able to make the functionality operate on a spatiotemporal input inconsistent with its actual physical state. The main conceptual challenge is to formulate extraction of spatiotemporal information within the simulation-based security framework. We introduce arguments of spatiotemporal knowledge, following the principle "I prove, therefore I am:" rather than defining physical presence directly through a mathematical relation, we define it operationally through the ability to complete a sound spatiotemporal verification protocol. Accordingly, an extractor recovers a spatiotemporal point from a successful prover and certifies its physical validity by using the extracted prover to succeed in an auxiliary spatiotemporal verification protocol. Building on this notion, we define universally composable (UC) security for spatiotemporal MPC, capturing privacy, physical consistency, and composability. We provide constructions achieving this new MPC notion. We first construct UC-secure commit-and-prove of spatiotemporal knowledge: in the CRS model under LWE against quantum provers without pre-shared entanglement, and in the QROM against quantum provers with unbounded pre-shared entanglement. Using these protocols, we obtain UC-secure spatiotemporal MPC from semi-honest post-quantum MPC. We also extend our framework to support quantum functionalities with classical spatiotemporal input.
Comments50 pages
