SaTC: CORE: Small: Collaborative: Hardware-assisted Plausibly Deniable System for Mobile Devices

移动的计算设备通常使用加密来保护敏感信息。然而，在移动的设备中使用的传统加密系统不能防御可以迫使移动终端所有者公开用于解密敏感信息的密钥的主动攻击者。这对那些成为民族国家目标的持不同政见者来说尤其令人担忧。这方面的一个例子是，一名人权工作者在压迫或冲突地区收集不良活动的证据，并将其以加密形式存储在移动终端上，然后被官员胁迫透露解密密钥。伪可否认加密（PDE）被提出来防御这样的对手谁可以强迫用户透露加密的敏感内容。然而，当在基于闪存的移动的设备中使用时，现有技术遭受若干问题，诸如由于在操作系统级和闪存转换层处处理读/写/擦除操作的方式而导致的弱可否认性、各种类型的侧信道攻击、以及移动的设备的计算和功率限制。该项目研究了一个独特的机会，以开发一个高效的（低开销）和有效的（高可否认性）硬件辅助PDE计划的主流移动的设备，是强大的对多快照对手。该项目包括重要的课程开发活动和面向K-12学生的外联活动。 该项目从根本上推进了移动的PDE系统，利用现有的硬件功能，如闪存转换层（FTL）固件和TrustZone，以实现低开销的高可否认性。具体而言，该项目开发的PDE系统具有以下功能：1）在移动的设备上使用原始闪存防御快照攻击; 2）消除危及可否认性的侧信道攻击; 3）可扩展以部署在主流移动的设备上; 4）有效地提供可用功能，如快速模式切换。该项目还为K-12学生和密歇根州新的网络安全教育合作伙伴关系区域网络安全教育合作（RCEC）开发了关于PDE和网络安全的新教材。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估而被认为值得支持。

Mobile computing devices typically use encryption to protect sensitive information. However, traditional encryption systems used in mobile devices cannot defend against an active attacker who can force the mobile device owner to disclose the key used for decrypting the sensitive information. This is particularly of concern to dissident users who are targets of nation states. An example of this would be a human rights worker collecting evidence of untoward activities in a region of oppression or conflict and storing the same in an encrypted form on the mobile device, and then being coerced to disclose the decryption key by an official. Plausibly Deniable Encryption (PDE) has been proposed to defend against such adversaries who can coerce users into revealing the encrypted sensitive content. However, existing techniques suffer from several problems when used in flash-memory-based mobile devices, such as weak deniability because of the way read/write/erase operations are handled at the operating systems level and at the flash translation layer, various types of side channel attacks, and computation and power limitations of mobile devices. This project investigates a unique opportunity to develop an efficient (low-overhead) and effective (high-deniability) hardware-assisted PDE scheme on mainstream mobile devices that is robust against a multi snapshot adversary. The project includes significant curriculum development activities and outreach activities to K-12 students. This project fundamentally advances the mobile PDE systems by leveraging existing hardware features such as flash translation layer (FTL) firmware and TrustZone to achieve a high deniability with a low overhead. Specifically, this project develops a PDE system with capabilities to: 1) defend against snapshot attacks using raw flash memory on mobile devices; and 2) eliminate side-channel attacks that compromise deniability; 3) be scalable to deploy on mainstream mobile devices; and 4) efficiently provide usable functions like fast mode switching. This project also develops novel teaching material on PDE and cybersecurity for K-12 students and the Regional Cybersecurity Education Collaboration (RCEC), a new educational partnership on cybersecurity in Michigan.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.