Secure File Storage On Cloud Using Hybrid Cryptography

Abstract

As technology today is moving forward exponentially, data exchange over the Internet has become a daily routine. Furthermore, businesses are growing internationally and offices are being established in a variety of different places throughout the world. This has resulted in the necessity to make data accessible and practical from any place. As a result, information sent via an may lead to critical security problems involving the breach of secrecy, authentication, and data integrity. This paper introduces a cloud storage system by utilising hybrid cryptography approach that leverages both advantages of symmetric key and asymmetric key cryptographic techniques. In our proposed system, the symmetric key algorithm AES is utilised to encrypt data, whereas the asymmetric key algorithm ElGamal is employed to perform key encryption before the data upload into cloud storage. Combining both symmetric key and asymmetric key methods alleviates privacy issues while increasing data confidentiality. In addition, a hash function which is SHA-2 is executed before the encryption process and after the decryption process. Both hash values are derived through a hashing procedure and matched in order to verify the data integrity. However, if the users' accounts were lost or stolen, all encryption would be meaningless. Hence, a Two-Factor Authentication (2FA) is also employed to minimise the abovementioned risk to achieve a greater security over the cloud environment.