With the advent of cloud-based quantum computing, it has become vital to provide strong guarantees that computations delegated by clients to quantum service providers have been executed faithfully. Secure—blind and verifiable—delegated quantum computing (SDQC) has emerged as one of the key approaches to address this challenge, yet current protocols lack at least one of the following three ingredients: composability, noise-robustness and modularity. To tackle this question, our paper lays out the fundamental structure of SDQC protocols, namely mixing two components: the computation which the client would like the server to perform and tests that are designed to detect a server’s malicious behaviour. Using this abstraction, our main technical result is a set of sufficient conditions on these components which imply the security and noise-robustness of generic SDQC protocols in the composable Abstract Cryptography framework. This is done by establishing a correspondence between these security properties and the error-detection capabilities of the test computations. Changing the types of tests and how they are mixed with the client’s computation automatically yields new SDQC protocols with different security and noise-robustness capabilities. This approach thereby provides the desired modularity as our sufficient conditions on test computations simplify the steps required to prove the security of the protocols and allows to focus on the design and optimisation of test rounds to specific situations. We showcase this by systematising the search for improved SDQC protocols for bounded-error quantum polynomial-time ( BQP ) computations. The resulting protocols do not require more hardware on the server’s side than what is necessary to blindly delegate the computation without verification, and they outperform all previously known results.

中文翻译：

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统一量子验证和错误检测：优化理论和工具


随着基于云的量子计算的出现，为客户委托给量子服务提供商的计算的忠实执行提供强有力的保证变得至关重要。安全、盲目且可验证的委托量子计算 (SDQC) 已成为应对这一挑战的关键方法之一，但当前协议至少缺乏以下三个要素之一：可组合性、噪声鲁棒性和模块化。为了解决这个问题，我们的论文列出了 SDQC 协议的基本结构，即混合两个组件：客户端希望服务器执行的计算和旨在检测服务器恶意行为的测试。使用这种抽象，我们的主要技术结果是这些组件的一组充分条件，这意味着可组合抽象密码学框架中通用 SDQC 协议的安全性和噪声鲁棒性。这是通过在这些安全属性和测试计算的错误检测能力之间建立对应关系来完成的。更改测试类型以及它们与客户端计算的混合方式会自动产生具有不同安全性和抗噪声能力的新 SDQC 协议。因此，这种方法提供了所需的模块化，因为我们的测试计算的充分条件简化了证明协议安全性所需的步骤，并允许专注于针对特定情况的测试轮次的设计和优化。我们通过系统化搜索用于有界误差量子多项式时间 (BQP) 计算的改进 SDQC 协议来展示这一点。 由此产生的协议不需要服务器端比在没有验证的情况下盲目委托计算所需的硬件更多的硬件，并且它们的性能优于所有先前已知的结果。