OQRAM：用于保护委托量子查询的不经意量子随机存取存储器
OQRAM: Oblivious Quantum Random Access Memory for Securing Delegated Quantum Queries
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中文总结 AI 辅助
该研究提出OQRAM，通过加密布局、相干地址掩码及诱饵检测等技术，实现隐私保护型委托量子查询，较全盲量子计算大幅降低量子资源与通信开销。
中文摘要 AI 辅助
量子查询是许多量子算法中的基本子例程，量子随机存取存储器（QRAM）为实现这类相干查询访问提供了自然方式。然而在委托场景中，标准QRAM查询接口会将敏感信息暴露给服务器。本文提出不经意量子随机存取存储器（Oblivious Quantum Random Access Memory，OQRAM），这是一种用于隐私保护型委托相干查询访问的密码学抽象。该协议包含离线刷新阶段与在线受保护查询阶段：数据库以加密且打乱的布局存储，每次查询通过基于量子安全伪随机置换（qPRP）的方法或量子一次性 pad（qOTP）的方法进行相干地址掩码保护。在采用的客户端模型中，在线保护仅在查询寄存器之外增加适度的量子开销，避免了等效本地QRAM构造所需的指数级量子资源。基于qPRP的变体还支持多查询使用，通过在多个查询间分配数据库刷新来减少经典通信；为应对恶意服务器，还加入了诱饵检测以强化隐私保护并实现概率性篡改检测。与全盲量子计算相比，该框架是专为私有委托QRAM访问定制的更轻量抽象，显著降低了客户端与服务器两侧的量子资源需求，并实现了量子通信的指数级减少。
英文摘要
Quantum query is a basic subroutine in many quantum algorithms, and Quantum Random Access Memory (QRAM) provides a natural way to realize such coherent query access. In delegated settings, however, a standard QRAM query interface can expose sensitive information to the server. This paper introduces oblivious QRAM, a cryptographic abstraction for privacy-preserving delegated coherent query access. The protocol consists of an offline refresh phase and an online protected query phase. The database is stored in an encrypted and shuffled layout, and each query is protected by coherent address masking using either a quantum-secure pseudorandom permutation (qPRP) based method or a quantum one-time pad (qOTP) based method. In the adopted client model, the online protection adds only modest quantum overhead beyond the query register, avoiding the exponential quantum resources that would otherwise be required by an equivalent local QRAM construction. The qPRP-based variant also supports multi-query use by distributing database refresh across multiple queries to reduce classical communication. To address malicious servers, decoy checks are further incorporated to strengthen privacy protection and enable probabilistic tampering detection. Compared with fully blind quantum computing, this framework provides a lighter abstraction tailored to private delegated QRAM access, significantly reducing quantum resource requirements on both the client and server sides and achieving an exponential reduction in quantum communication.
