A Universally Composable Key Management System Using Trusted Hardware

The management of cryptographic keys within cloud services is crucial for ensuring data security but raises significant privacy and trust issues. This paper addresses the vulnerabilities of conventional key management systems (KMS), where cloud service providers might access and control user keys without consent, as well as intercept and misappropriate users’ secret data. To address these concerns, we propose a KMS protocol that leverages trusted hardware to minimize the level of trust required in cloud service providers. Our protocol ensures that the customer master key remains confined within a secure enclave, inaccessible to the service provider, and incorporates a bidirectional authentication mechanism to protect against impersonation by malicious providers. Within the universally composable framework, we design and analyze our protocol and rigorously prove its security. As a result, our designed KMS can be used in composition with any system, and its security can be guaranteed under any conditions. We also develop a prototype KMS based on Intel Trust Domain Extensions and evaluate its performance, emphasizing the system’s viability in real-world applications. The source code for our prototype is publicly available.