Description

ABSTRACT

     Cloud Computing is a Model for enabling Convenient, on-demand network access to a shared pool of configurable computing resources (e.g.  networks, servers, storage, applications, and services)that can be rapidly provisioned and released with management effort or service provider interaction. Cloud technology allows for much more efficient computing by centralizing storage, memory, processing and bandwidth. The security is the major issue in the cloud computing. The issue is overcome by the encryption. The various encryption standards ensure the cloud security. Attribute-based encryption (ABE) is a vision of public key encryption 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 outsourced encryption method the user provides a transformation key to the cloud to translate any ABE cipher text into simple cipher text and it only incurs a small computational overhead for the user to recover the plaintext from the transformed ciphertext.We cannot guarantee that the cloud server will perform the transformation correctly. The proposed system introduces the Verifiable Outsourced Encryption so that the user can check the correctness of the transformation performed by the cloud server and the user let to know the data is not modified by the untrusted servers.