Blockchain based Secure Group Data Collaboration in Cloud with Differentially Private Synthetic Data and Trusted Execution Environment.

Data collaboration with cloud technologies is becoming more popular for personal use as well as business applications. Due to the increasing data protection regulations worldwide, different cryptographic techniques have been designed to enable secure data sharing for a user or a group of users. Although, these techniques have seen enterprise adoption, they fail to offer data visibility as data remains encrypted throughout the data sharing routine. This is why these techniques fail to offer a key features to data users, e.g., joining different datasets together and sharing it with all the users involved. This paper presents a blockchain based architecture for secure data collaboration in cloud using differentially private synthetic data and trusted execution environment (TEE). The proposed solution protects data confidentiality and integrity with TEEs, supports public-key infrastructure (PKI) with blockchain, and prevents privacy leakages with synthetic data. The results show that our synthetic data performs as good as real data and demonstrates how different users can securely aggregate their datasets and openly share among themselves.