Securing Data Storage

计算机用户通过各种存储介质(SD卡、U盘、笔记本电脑、电子邮件附件等)存储海量的个人数据和知识产权，而这些用户没有得到任何关于存储安全的保证。有些技术，如加密，用于某些地方或保护传输，但它们是存储数据的方面，而不是与数据绑定的策略。存在各种改进存储的技术，如加密、安全删除、可否认存储、历史独立性和存储虚拟化。尽管如此，它们经常不一起使用，并且没有一种在实践中被广泛使用。虽然这对一些用户来说是次优的，但它完全辜负了世界上在敌对环境中工作的更极端的用户，如军事、记者和政治异见人士。这项工作将通过将安全作为标准文件系统的一部分来提高存储安全的最低标准。该研究计划有两个主要组成部分。一个重点是提高便携式闪存的安全性，作为第一道防线。闪存被广泛使用，但它有一个细微的特点：数据不能被覆盖。取而代之的是，新数据被写入错位，并且只能以大的粒度进行删除。这对存储、读取和删除数据的算法和文件系统有重大影响。它还使几个通常很容易提供的安全功能变得极其复杂。在深入了解闪存文件系统设计挑战的基础上，这项工作将设计下一代闪存文件系统，目标是在不显著降低最终文件系统的可用性和性能的情况下，协调加密、安全删除、可否认性和其他功能。第二个组成部分是开发可用的技术，允许用户指定数据的存储策略，而不必指定要使用的特定存储介质。目前，用户将文件放在U盘上，使其成为便携设备，或者通过电子邮件发送给自己，以便在其他电脑上访问。用户经常进行临时备份，并将数据存储在多个位置，而不清楚数据是如何存储的，甚至是在哪里存储的。目前人们用来保护数据的技术是不方便的、不安全的、不可靠的或不可用的。我们将创建一个虚拟存储设备(VSD)来解决这些问题。VSD将成为数据进出存储终端的路由器，允许用户专注于他们所需的存储属性，如安全性、速度、可靠性和成本。VSD将从对用户有意义的策略和风险属性中提取存储介质的物理属性(例如，它们位于何处以及如何连接)。由于数据存储与物理计算设备分离，用户将无处不在地访问、处理和计算他们的数据。

Computer users store immense amounts of personal data and intellectualproperty across a variety of storage media (SD cards, USB sticks, laptops,attachments in e-mails, etc.), and these users are not given any guaranteesabout storage security. Some techniques, like encryption, are used in someplaces or to secure transmissions, but they are an aspect of what stores thedata and not a policy tied to the data.There exists a variety of techniques for improving storage, such as encryption, securedeletion, deniable storage, history independence, and storage virtualization.Despite that, they are frequently not used together and none are widely used inpractice. While this is sub-optimal for some users, it completely fails the world'smore-extreme users working in hostile environments, such as military, journalists,and political dissidents. This work will raise the minimum standard for storage securityby providing security as part of standard file systems.The research program has two broad components. One focuses on improving thesecurity of portable flash-based storage to act as a first line of defense.Flash memory is widely used but it has a characteristic nuance: data cannot beoverwritten. Instead new data is written out of place, and deletion can onlyhappen at a large granularity. This has significant implications on thealgorithms and file systems that store, read, and delete data. It also severelycomplicates several security features that would normally be easilyprovided. Building on a deep understanding of the challenges in designing flashfile systems, this work will design a next-generation flash file system with thegoals of harmonizing encryption, secure deletion, deniability, and other featureswithout a significant cost in the usability and performance of the resulting filesystem.The second component is developing usable techniques to allow users to specifystorage policy for data without having to specify the particular storage mediumto use. Currently, users put files on USB sticks to make them portable, ore-mail it to themselves to access it on other computers. Users frequently makead hoc backups, and store data in multiple places without a clear understandingof how, or even where, the data is stored. Current techniques people use tosafeguard their data are inconvenient, insecure, unreliable, or unusable. We willcreate a Virtual Storage Device (VSD) to address these problems. The VSD willbe a router for data to and from storage endpoints, allowing users to focus onthe storage properties that they desire, such as security, speed, reliability, andcost. The VSD will abstract the physical properties of storage media (e.g., wherethey are located and how they are connected) from the policy and risk attributesthat are meaningful to the user. Users will access, work on, and compute withtheir data ubiquitously as the data storage is separated from the physicalcomputation devices.