CP-ABSc-AODs : CIPHERTEXT-POLICY ATTRIBUTE-BASED SIGNCRYPTION WITH ACCOUNTABLE OUTSOURCED DESIGNCRYPTION - AN ENHANCED SECURE DATA SHARING SCHEME

Abstract

 Cloud computing is becoming the powerful and popular model to all internet users as they can use the required resources from the available pool. As users are freed from operational and maintenance costs, it is very cheaper to pay only for what they use. Also IT companies started migrating their huge data and applications to the cloud which in turn is managed by the cloud service provider (CSP). The CSP may not be trustable and so data owners as well as users require the stored data to be secured even from illegal access from the CSP itself. Since cloud geographically disperses the content while storing, data location is hidden and data can be vulnerable questioning the confidentiality and integrity of the data. Achieving confidentiality requires to follow cryptographic approaches to give access only to authorized and intended users. This paper proposes an efficient Ciphertext-Policy Attribute-Based Signcryption with Accountable Outsourced Designcryption (CP-ABSc-AODs) to securely share data that supports confidentiality, accurate access control, authenticity, message integrity as well as sender privacy. Signer’s anonymity is maintained using signcryption. Designcryption is a complicated process with heavy  computational overhead and so it is outsourced to a Ciphertext Transformation Server benefiting the user with minimal computational overhead. This paper also concludes that the additional communication overhead due to outsourcing is tolerable.