Collaborative Key Management in Ciphertext Policy Attribute Based Encryption for Cloud

Abstract

With improvement in technology, sharing data with other is convenient. Sharing of cloud based outsource data on mobile devices require some promising infrastructure to secure data over cloud. Ciphertext policy attribute-based encryption is a technique, which provides finegrained access to outsourced data over cloud. This technique has some drawback with key management. Frontend device like mobile, tab etc. of client side has limited privacy protection, so if keys are held by them client risk key exposure that is hardly noticed. To overcome these issues collaborative key management protocol in Ciphertext policy attribute based encryption is propose, in this protocol private keys are generated issued and stored in distributed manner and finegrained immediate attribute revocation mechanism is provided for key update. Multiple key authorities manage their attributes independently. Different attribute set are used which allows user to define their own access policy, so at time of decryption client need to match the access policy attribute first many users can be allowed to encrypt/decrypt different part of data. This protocol not only solve problem of key exposure but also help to reduce client decryption overhead.