Enhanced Cloud Data Security Through Verifiable Cipher Policy Based Encryption

Cloud storage enables users to remotely store their data and enjoy the on-demand high quality cloud applications without the burden of local hardware and software management. Though the benefits are clear, such a service is also relinquishing users’ physical possession of their outsourced data, which inevitably poses new security risks towards the correctness of the data in cloud. In order to address this new problem and further to achieve a secure and dependable cloud storage service, we develop a new cryptosystem for fine-grained sharing of encrypted data that we call Cipher-Policy Attribute-Based Encryption (CP-ABE) with verifiable outsourced decryption. In our cryptosystem, cipher texts are labeled with sets of attributes and private keys are associated with access structures that control which cipher texts a user is able to decrypt. This scheme also eliminates the overhead caused due to large number of pairing operations in decryption. Attribute-based encryption (ABE) has been envisioned as a promising cryptographic primitive for realizing secure and flexible access control. So, in order to check the correctness of transformation done, we introduce the concept of verifiability. The proposed design consist of efficient methods that enable on-demand data correctness verification. ABE[Attribute based Encryption] extends the ASBE algorithm with a hierarchical structure to improve scalability and flexibility while at the same time inherits the feature of fine-grained access control of ABE. A traditional Cloud security concept ensures the Identity based Cryptography which results in secured outsourcing of cloud data.