TC: Small: Risk Aware Query Processing in Mixed Security Database Environments

在数据库查询处理期间，数据在不同的系统组件之间迁移，每个系统组件可能提供不同级别的安全保证，并且可能容易受到不同的攻击。如果底层数据（或其中的一部分）是敏感的，那么数据迁移，特别是从安全组件迁移到相对不安全的组件，可能会增加数据丢失的风险。该建议采用“基于风险”的安全方法，其中所提出的研究不是设计防止攻击的方法，而是通过各种组件控制查询处理期间的数据流，从而在暴露风险和系统性能之间取得平衡。风险感知查询处理技术在两种情况下进行了探讨：(a)一个独立的数据库服务器，其中磁盘上的数据是加密存储的（因此是安全的），但在查询处理期间以明文形式加载到内存中。(b)云计算环境，在峰值负载期间，查询（和相应数据）从（相对安全的）私有存储发送到（相对不安全的）公共云基础设施进行处理，这种现象称为cloudbursting。在这两种设置中，我们探索了共同优化查询执行的技术，以同时最小化披露风险和性能成本。该研究提供了一种基于防止攻击的传统技术的补充方法，以支持数据库系统环境中的实际安全性。该项目旨在帮助启动数据库安全研究的新方向，探索限制风险的技术（而不仅仅是防止攻击）。这项研究如果成功，将使基于云的数据管理解决方案更加安全，甚至对那些有大量数据保密问题的应用程序也会提高其采用率。最后，计划的研究、系统开发和教育活动有望显著提高学生的教育体验。

During database query processing, data migrates across different system components each of which may offer different levels of security guarantees and may be susceptible to different attacks. If the underlying data (or part of it) is sensitive, data migration, especially from secure components to those that are relatively insecure could increase risk of data loss. This proposal takes a "risk-based" approach to security wherein instead of designing approaches to prevent attacks, the proposed research controls flow of data during query processing through various components in such a way to strike a balance between risk of exposure and system performance. Risk-aware query processing techniques is explored in two settings: (a) A stand-alone database server where data on disks is stored encrypted (and is hence secure) but is loaded in plaintext into memory during query processing. (b) Cloud computing environment where, during peak load queries (and corresponding data) are shipped from (relatively secure) private storage to be processed at (relatively insecure) public cloud infrastructure, a phenomena known as cloudbursting. In both these settings, techniques to co-optimize query execution to simultaneously minimize both disclosure risks as well as performance costs are explored. The research offers a complementary approach to traditional techniques based on preventing attacks to support practical security in the context of database systems.The project seeks to help launch a new direction to database security research that explores techniques to limit risks (instead of only preventing attacks). The research, if successful, will make cloud-based data management solutions more secure increasing the rate of their adoption even for applications that have substantial data confidentiality concerns. Finally, the planned research, system development, and educational activities are expected to significantly enhance the educational experience of students.