Indian Journal of Science and Technology

Abstract

Objective: We propose a decentralized access controlled scheme for secure data storage in clouds that supports public key encryption. Our scheme also has the added feature of generating attribute key-value pairs with ciphers for easily granting permission to transfer data. The scheme prevents tampering by performing integrity checks and verifying the message digest. Methods/Statistical Analysis: In the proposed scheme, the data is transferred by public key encryption among users by the RSA algorithm. The attributes are sent via e-mail and can trigger an encrypted transfer of data stream, which can be decrypted only by the validated users. The cloud does not store the private keys of users and only stores public keys. Findings: The computation and transfer of cipher text, and storage overheads are the same as a centralized scheme. The decentralization of data makes it private and the encrypted copy on the cloud provides a redundant backup which cannot be read by the cloud. The performance of the scheme has been measured by time complexity of the operations using big-O notation. Applications/Improvement: The scheme can be improved with signatures. Signatures can be studied in detail and come in various types. Some signatures verify the authenticity of files while other complex ones work with multi-party authentication. 
Keywords: Access Control in Cloud, Cryptography, MVC, RSA