NeXUS: Practical and Secure Access Control on Untrusted Storage Platforms using Client-Side SGX
NeXUS: Practical and Secure Access Control on Untrusted Storage Platforms using Client-Side SGX
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DOI：
10.1109/dsn.2019.00049
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发表时间：
2019-06
期刊：
影响因子：
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通讯作者：
J. B. Djoko;Jack Lange;Adam J. Lee
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文献类型：
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作者：
J. B. Djoko;Jack Lange;Adam J. Lee
随着 Google Drive 和 Dropbox 等文件共享服务在个人和企业工作流程中的日益普及，保护客户外包数据免遭未经授权的访问或篡改仍然是一个主要的安全问题。针对此问题的现有加密解决方案通常需要服务器端支持，涉及用户方面的重要密钥管理，并且在访问撤销时遭受严重的重新加密惩罚。这种性能开销和管理负担的结合使得此类解决方案在需要高性能、平台无关、动态共享用户内容的情况下不受欢迎。我们推出 NEXUS，这是一种可堆叠文件系统，它利用可信硬件为存储在不可信平台上的用户文件提供机密性和完整性。 NEXUS 的设计明确是为了平衡安全性、可移植性和性能：它支持在任何公开文件访问 API 的平台上动态共享受保护卷，而无需服务器端支持，支持使用细粒度访问控制策略来允许选择性共享，并避免与其他访问控制加密方法相关的密钥撤销和文件重新加密开销。这种功能组合是通过使用客户端 Intel SGX enclave 实现的，该客户端用于保护和共享 NEXUS 卷，确保加密密钥永远不会离开 enclave 内存，并避免在撤销访问权限时重新加密文件的需要。我们实现了一个在 AFS 文件系统之上运行的 NEXUS 原型，并表明它对于各种常见文件和数据库操作会产生 2 倍的开销。
With the rising popularity of file-sharing services such as Google Drive and Dropbox in the workflows of individuals and corporations alike, the protection of client-outsourced data from unauthorized access or tampering remains a major security concern. Existing cryptographic solutions to this problem typically require server-side support, involve non-trivial key management on the part of users, and suffer from severe re-encryption penalties upon access revocations. This combination of performance overheads and management burdens makes this class of solutions undesirable in situations where performant, platform-agnostic, dynamic sharing of user content is required. We present NEXUS, a stackable filesystem that leverages trusted hardware to provide confidentiality and integrity for user files stored on untrusted platforms. NEXUS is explicitly designed to balance security, portability, and performance: it supports dynamic sharing of protected volumes on any platform exposing a file access API without requiring server-side support, enables the use of fine-grained access control policies to allow for selective sharing, and avoids the key revocation and file re-encryption overheads associated with other cryptographic approaches to access control. This combination of features is made possible by the use of a client-side Intel SGX enclave that is used to protect and share NEXUS volumes, ensuring that cryptographic keys never leave enclave memory and obviating the need to reencrypt files upon revocation of access rights. We implemented a NEXUS prototype that runs on top of the AFS filesystem and show that it incurs ×2 overhead for a variety of common file and database operations.