Secured and Verifiable Approach for Attribute Based Encryption in Cloud Computing

Cloud Computing has changed the phenomena of IT industry completely. It allows access to highly scalable, inexpensive, on demand computing resources that can execute the code and store data that are provided. But adoption and approach to cloud computing applies only if the security is ensured. Cloud computing is lacking in security, confidentiality and visibility. Secure the cloud means to secure the storage. Security is achieved by the encryption. There are various encryption standards to ensure the cloud security. Attribute-based encryption (ABE) is public key encryption technique that allows users to encrypt and decrypt messages based on user attributes. In a typical implementation, the size of the cipher text is proportional to the number of attributes associated with it and the decryption time is proportional to the number of attributes used during decryption. To reduce the decryption time in cloud outsourced decryption technique is used. By providing a transformation key to the cloud ABE cipher text is converted into simple cipher text and it only incurs a small computational overhead for the user to recover the plaintext from the transformed ciphertext.. To ensure that transformation performed by cloud server is correct and the data is not modified by the untrusted servers proposed system is introduced. This provides secured and Verifiable Outsourced decryption.