Traffic analysis attacks can counteract end-to-end encryption and use leaked communication metadata to reveal information about communicating parties. With an ever-increasing amount of traffic by an ever-increasing number of networked devices, communication privacy is undermined. Therefore, Anonymous Communication Systems (ACSs) are proposed to hide the relationship between transmitted messages and their senders and receivers, providing privacy properties known as anonymity, unlinkability, and unobservability. This article aims to review research in the ACSs field, focusing on Dining Cryptographers Networks (DCNs). The DCN-based methods are information-theoretically secure and thus provide unconditional unobservability guarantees. Their adoption for anonymous communications was initially hindered because their computational and communication overhead was deemed significant at that time, and scalability problems occurred. However, more recent contributions, such as the possibility to transmit messages of arbitrary length, efficient disruption handling and overhead improvements, have made the integration of modern DCN-based methods more realistic. In addition, the literature does not follow a common definition for privacy properties, making it hard to compare the approaches' gains. Therefore, this survey contributes to introducing a harmonized terminology for ACS privacy properties, then presents an overview of the underlying principles of ACSs, in particular, DCN-based methods, and finally, investigates their alignment with the new harmonized privacy terminologies. Previous surveys did not cover the most recent research advances in the ACS area or focus on DCN-based methods. Our comprehensive investigation closes this gap by providing visual maps to highlight privacy properties and discussing the most promising ideas for making DCNs applicable in resource-constrained environments.
翻译:交通分析攻击可以抵消终端到终端的加密,并使用泄漏的通信元数据披露通信方的信息。随着网络设备越来越多,通信隐私受到破坏,通信的保密性受到破坏,因此建议匿名通信系统隐藏传输信息与其发件人和接收人之间的关系,提供被称为匿名、互不连接和不易观测的隐私属性。本篇文章旨在审查ACSS领域的研究,侧重于Dining加密器网络(DCNs),基于DCN的方法是信息理论安全,因此提供了无条件的不可观测性保障。最初,匿名通信的采用受到阻碍,因为它们的计算和通信间接费用被认为在那个时候相当重要,而且出现了可缩放问题。然而,最近的贡献,如传递任意长度信息的可能性、高效的干扰处理和对管理费的改进,使得基于现代DCN方法的整合更加现实化。此外,文献没有遵循关于隐私属性的通用定义,因此很难将方法的准确性化,因此难以对方法进行更接近的可视性保证。因此,大多数对匿名通信的采用都受到阻碍,因为它们的计算和通信的间接性研究术语对ACSLCS的最近的重点进行了更新。