Decentralized SGX-Based Cloud Key Management

The adoption of cloud computing is expanding at an astonishing pace for personal and professional usage. The high computational power and storage capacity have created a preference for traditional on-premise service provisioning. However, security remains the primary issue when dealing with the cloud paradigm. Encryption schemes have been considered a straightforward approach to protecting sensitive data. Yet, several key management schemes are vulnerable to various threats that weaken the long-term efficiency of the encryption scheme. This paper proposes MultiSGX-KMS, an efficient and secure cloud key management scheme. The suggested scheme aims to protect exchanged user keys while ensuring fault tolerance using secret sharing and trusted execution environments. In addition, the encryption keys are deployed in the SGX instance in the cloud while being fully controlled by the end user. The scheme is robust against proactive attacks and mitigates against a computationally bounded attacker without assuming a possible hardware attack on an SGX enclave. The proposed scheme presents a limited overhead of 0.1% for a file size of 50 MB compared to the traditional approach. The overhead further decreases proportionally as file sizes increase.