Efficient Attribute Revocation Scheme for Multi-authority Attribute Cloud Storage System

Abstract

Cloud computing is an emerging computing tool in which resources accessed as a service over Internet on pay for use basis. Most of the organization are changing their storage server to cloud server without any botheration. It is a great challenge for the cloud service provider to attract the customers to store their sensitive data/file in the cloud storage. Service provisioning with respect to privacy preservation and data security is an area of concern. In general the cloud servers are being deployed on different trusted domain. Fine grained access control is major area of concern in data outsourcing and sharing in untrusted cloud server. There will be need to encrypt sensitive data and store them in cloud server and disclose decryption key to authorized users. But drawback of this method is that owner of file has to know receivers prior to encryption which is not possible in most of the case. Cipher text Policy Attribute Based Encryption (CPABE) is one of the technique that is used for fine grained access control in untrusted server. This techniques used to keep shared data confidential even if data is stored on remote server. It uses trusted authority to issue attribute and distribute key to users in the system. There can be multiple authority in a CPABE system and each authority issue attributes and keys independent of each other. Efficient decryption and attribute revocation is major area of research in multi authority cloud storage system. Attribute revocation in multi authority cloud storage system should achieve both forward and backward security.