arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2008.03642cs.ITmath.IT
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请求隐私缓存对合谋用户的基本限制

Fundamental Limits of Caching for Demand Privacy against Colluding Users

Qifa Yan, Daniela Tuninetti

摘要:

这项工作调查的问题,需求隐私对串通用户的共享链接编码缓存系统,其中没有一个子集的用户可以了解任何信息的需求,其余用户。这里使用的隐私的概念是强于过去的工作中采用的类似的概念,是出于实际需要,以确保隐私,无论文件的分布。考虑了两种情况:单文件检索(SFR)和线性函数检索(LFR),在后一种情况下,每个用户都需要服务器上文件的任意线性组合。本文的主要贡献是一个新的可实现的方案,LFR,称为私钥方案,和一个新的信息论逆界的SFR。显然,由于SFR是LFR的特殊情况,LFR的可实现方案也适用于SFR,并且SFR的逆也是LFR的有效逆。通过比较的性能,可实现的方案与本文推导出的逆界(对于小缓存大小政权)和现有的逆界没有隐私约束(在剩余的内存制度),通信负载的隐私密钥方案原来是最佳的常数乘法间隙内的所有参数制度。数值结果表明,新方案的性能优于已有的基于虚拟用户思想的方案,同时也满足了更强的用户隐私概念,能够有效地防止合谋用户的攻击.此外,隐私密钥方案享有比已知的基于虚拟用户的方案低得多的子分组化。

英文摘要:

This work investigates the problem of demand privacy against colluding users for shared-link coded caching systems, where no subset of users can learn any information about the demands of the remaining users. The notion of privacy used here is stronger than similar notions adopted in past work and is motivated by the practical need to insure privacy regardless of the file distribution. Two scenarios are considered: Single File Retrieval (SFR) and Linear Function Retrieval (LFR), where in the latter case each user demands an arbitrary linear combination of the files at the server. The main contributions of this paper are a novel achievable scheme for LFR, referred as privacy key scheme, and a new information theoretic converse bound for SFR. Clearly, being SFR a special case of LFR, an achievable scheme for LFR works for SFR as well, and a converse for SFR is a valid converse for LFR as well. By comparing the performance of the achievable scheme with the converse bound derived in this paper (for the small cache size regime) and existing converse bounds without privacy constraints (in the remaining memory regime), the communication load of the privacy key scheme turns out to be optimal to within a constant multiplicative gap in all parameter regimes. Numerical results show that the new privacy key scheme outperforms in some regime known schemes based on the idea of virtual users, which also satisfy the stronger notion of user privacy against colluding users adopted here. Moreover, the privacy key scheme enjoys much lower subpacketization than known schemes based on virtual users.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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