Combining Elliptic Curve Cryptography and Blockchain Technology to Secure Data Storage in Cloud Environments.

Many encryption strategies have been applied to ensure data confidentiality and improve cloud security. The most recent cryptosystems are based on homomorphic (HE), attribute-based (ABE), and hybrid encryption. However, most of them suffer from numerous drawbacks: high time consumption, encrypted message size, and some vulnerabilities. Hence, a secure method is highly required to get a satisfying security level while keeping the computational complexity reduced. This paper outlines a novel technique that combines elliptic curve cryptography (ECC) and Blockchain technology. The data is first encoded using the Elliptic Curve Integrated Encryption Scheme, then signed using signed using the Elliptic Curve Digital Signature Algorithm, and finally confirmed by the blockchain network before being stored in the cloud. The performance evaluation results prove that the proposed system is highly resistant to man-in-the-middle and replay attacks and performs better than a set of existing solutions in terms of cryptography cost, encryption/decryption time, and algortithm complexity.