An Efficient Probabilistic tracing scheme for Multi Authority CP-ABE for Cloud Storage

Cloud storage is used passionately for online data storage. Cipher text Policy-Attribute Based Encryption (CP-ABE) is considered as promising solution for data access control for the outsourced data stored in cloud servers as the user satisfying the access structure can only access the encrypted data. In CP-ABE, there may exist multiple user with the same decryption key hence this leads to severe issue of key abuse. The existing CP-ABE system does not provide any good mechanism to address this problem hence the malicious user cannot be traced. This paper proposes an efficient mechanism for tracing the malignant user as well as semi-trusted attribute authorities who may re-distribute the key to traitors.