Caching content at the edge network is a popular and effective technique widely deployed to alleviate the burden of network backhaul, shorten service delay and improve service quality. However, there has been some controversy over privacy violations in caching content at the edge network. On the one hand, the multi-access open edge network provides an ideal entrance or interface for external attackers to obtain private data from edge caches by extracting sensitive information. On the other hand, privacy can be infringed on by curious edge caching providers through caching trace analysis targeting the achievement of better caching performance or higher profits. Therefore, an in-depth understanding of privacy issues in edge caching networks is vital and indispensable for creating a privacy-preserving caching service at the edge network. In this article, we are among the first to fill this gap by examining privacy-preserving techniques for caching content at the edge network. Firstly, we provide an introduction to the background of privacy-preserving edge caching (PPEC). Next, we summarize the key privacy issues and present a taxonomy for caching at the edge network from the perspective of private information. Additionally, we conduct a retrospective review of the state-of-the-art countermeasures against privacy leakage from content caching at the edge network. Finally, we conclude the survey and envision challenges for future research.

中文翻译：

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网络边缘隐私保护缓存调查：分类、解决方案和挑战


在边缘网络缓存内容是一种广泛部署的流行且有效的技术，用于减轻网络回传负担、缩短服务延迟和提高服务质量。然而，在边缘网络中缓存内容时侵犯隐私一直存在一些争议。一方面，多路接入的开放边缘网络为外部攻击者通过提取敏感信息从边缘缓存中获取私有数据提供了理想的入口或接口。另一方面，奇怪的边缘缓存提供商可能会通过缓存跟踪分析来侵犯隐私，以实现更好的缓存性能或更高的利润。因此，深入了解边缘缓存网络中的隐私问题对于在边缘网络创建隐私保护缓存服务至关重要且不可或缺。在本文中，我们率先通过研究在边缘网络缓存内容的隐私保护技术来填补这一空白。首先，我们介绍了隐私保护边缘缓存 （PPEC） 的背景。接下来，我们总结了关键的隐私问题，并从私人信息的角度提出了边缘网络缓存的分类法。此外，我们还对边缘网络内容缓存导致隐私泄露的最新对策进行了回顾性审查。最后，我们总结了调查并设想了未来研究的挑战。