Safeguarding Data through Homomorphic Cryptosystems in Cloud Storage

In this chapter, we have given implementation and performance details of two homomorphic encryption schemes, Rivest Shamir Adleman (RSA) and Paillier. The RSA is multiplicative homomorphic scheme where the Paillier is additive homomorphic scheme. Cloud computing is a revolutionary technology that enables users to access and utilize computing resources, including servers, storage, databases, and software applications, over the internet. It operates on a vast network of remote servers, allowing seamless scalability, cost-efficiency, and flexible data management. By allowing users to use remote resources, cloud computing lightens the load on local storage. But using these services creates a whole new set of issues. Since users have no control over the data they save on those storage devices, it is crucial to accomplish data authentication and secrecy. Since not every user possesses that level of knowledge, they can ask Trusted Verifier (TV), an authorized third party, to do data verification on their behalf in order to ensure that the outsourced data is intact. Since the data owner stores the data on the cloud in an encrypted format, it becomes difficult to check the integrity of the data without decrypting. But by using homomorphic encryption schemes the integrity checking can be made possible without original copy. Using the homomorphic properties of RSA or Paillier cryptosystems, we can check the intactness of remotely stored data without having the original copy, thus can achieve public auditability. Due to their partial homomorphism, both techniques have limited functionality. Owing to these methods' homomorphic nature, the original contents will remain hidden during the verification process. By preserving secrecy, this architecture will enable data authentication.