SoK: Making Sense of Censorship Resistance Systems
SoK: Making Sense of Censorship Resistance Systems
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DOI：
10.1515/popets-2016-0028
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发表时间：
2016-10
影响因子：
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通讯作者：
Sheharbano Khattak;T. Elahi;Laurent Simon;C. Swanson;S. Murdoch;I. Goldberg
中科院分区：
文献类型：
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作者：
Sheharbano Khattak;T. Elahi;Laurent Simon;C. Swanson;S. Murdoch;I. Goldberg
越来越多的国家出于各种原因在不同规模上实施互联网审查。出现了几个审查抵抗系统（CRS）来帮助绕过这些封锁。审查员攻击场景的多样性导致了军备竞赛，导致CRS的进化速度惊人。CRS固有的复杂性和这一领域工作的广度使得很难将审查员的能力和审查抵抗战略置于背景之中。为了应对这些挑战，我们对CRS部署的工具以及学术文献中讨论的工具进行了全面的调查，以通过其威胁模型和相应的防御来系统化审查抵抗系统。为此，我们首先勾勒出一个全面的攻击模型，列出审查员的能力，再加上审查的范围上的讨论，以及影响审查员的决定的动态。接下来，我们提出了一个评估框架，通过其安全性，隐私性，性能和可部署性来系统化审查抵抗系统，并展示这些系统如何映射到攻击模型。我们为审查抵抗系统确定的每个功能阶段都这样做：通信建立，涉及客户加入审查抵抗系统所需的信息的分发和检索;对话，进行实际的信息交换。我们的评估使我们能够识别文献中的差距，质疑起作用的假设，并探索可能的缓解措施。
Abstract An increasing number of countries implement Internet censorship at different scales and for a variety of reasons. Several censorship resistance systems (CRSs) have emerged to help bypass such blocks. The diversity of the censor’s attack landscape has led to an arms race, leading to a dramatic speed of evolution of CRSs. The inherent complexity of CRSs and the breadth of work in this area makes it hard to contextualize the censor’s capabilities and censorship resistance strategies. To address these challenges, we conducted a comprehensive survey of CRSs-deployed tools as well as those discussed in academic literature-to systematize censorship resistance systems by their threat model and corresponding defenses. To this end, we first sketch a comprehensive attack model to set out the censor’s capabilities, coupled with discussion on the scope of censorship, and the dynamics that influence the censor’s decision. Next, we present an evaluation framework to systematize censorship resistance systems by their security, privacy, performance and deployability properties, and show how these systems map to the attack model. We do this for each of the functional phases that we identify for censorship resistance systems: communication establishment, which involves distribution and retrieval of information necessary for a client to join the censorship resistance system; and conversation, where actual exchange of information takes place. Our evaluation leads us to identify gaps in the literature, question the assumptions at play, and explore possible mitigations.