We present Shufflecake, a new plausible deniability design to hide the existence of encrypted data on a storage medium making it very difficult for an adversary to prove the existence of such data. Shufflecake can be considered a ``spiritual successor'' of tools such as TrueCrypt and VeraCrypt, but vastly improved: it works natively on Linux, it supports any filesystem of choice, and can manage multiple volumes per device, so to make deniability of the existence of hidden partitions really plausible. Compared to ORAM-based solutions, Shufflecake is extremely fast and simpler but does not offer native protection against multi-snapshot adversaries. However, we discuss security extensions that are made possible by its architecture, and we show evidence why these extensions might be enough to thwart more powerful adversaries. We implemented Shufflecake as an in-kernel tool for Linux, adding useful features, and we benchmarked its performance showing only a minor slowdown compared to a base encrypted system. We believe Shufflecake represents a useful tool for people whose freedom of expression is threatened by repressive authorities or dangerous criminal organizations, in particular: whistleblowers, investigative journalists, and activists for human rights in oppressive regimes.

翻译：我们提出Shufflecake——一种新型可否认加密设计方案，用于隐藏存储介质中加密数据的存在性，使攻击者极难证明此类数据的存在。Shufflecake可视为TrueCrypt和VeraCrypt等工具的"精神继承者"，但具有显著改进：原生支持Linux系统、兼容任意文件系统、可在单个设备上管理多个卷，从而使隐藏分区存在的可否认性真正具有可行性。与基于ORAM的解决方案相比，Shufflecake具有极高的运行速度和更简洁的架构，但缺乏针对多快照攻击者的原生防护能力。然而，我们讨论了由其架构支撑的安全扩展方案，并论证了这些扩展足以防御更强大攻击者的技术依据。我们在Linux内核中实现了Shufflecake工具并增添了实用功能，性能基准测试表明，相比基础加密系统，其性能损耗极小。我们相信，对于言论自由受到专制政权或危险犯罪组织威胁的人群（特别是举报人、调查记者及威权体制下的人权活动人士）而言，Shufflecake是一个实用工具。