Efficient Lattice CPABE AC Scheme Supporting ReducedOBDD Structure for CCNNDN In line with the proposed 5th Generation network, content centric networknamed data networking (CCNNDN) has been offered as one of the promising paradigms to cope with the communication needs of future realistic network communications. CCNNDN allows network communication based on content names and also allows users to obtain information from any of the nearest intermediary caches on the network. Due to that, the ability of cached content to protect itself is essential since contents can be cached on any node everywhere, and publishers may not have total control over their own published data. The attribute based encryption (ABE) scheme is a preferable approach, identified to enable cached contents to be selfsecured since it has a special property of encryption with policies. However, most of the proposed ABE schemes for CCNNDN suffer from some loopholes. They are not flexible in the expression of access policy, they are inefficient, they are based on bilinear maps with pairings, and they are vulnerable to quantum cryptography algorithms. Hence, we propose the ciphertext policy attribute based encryption access control (CPABE AC) scheme from a lightweight ideal lattice based on ring learning with error (RLWE) problem, and demonstrated its use in practical applications. The proposed scheme is proved to be secure and efficient under the decision ring LWE problem in the selective set model. To achieve an efficient scheme, we used an efficient trapdoor technique and the access tree representation of access structure describing the access policies was modified into a new structure, based on a reduced ordered binary decision diagram (reduceOBDD). This access structure can support Boolean operations such as AND, NOT, OR, and threshold gates. The final result showed that the proposed scheme was secure and efficient for applications, thereby supporting CCNNDN as a promising paradigm.

Practical traceable multiauthority CPABE with outsourcing decryption and access policy updation Abstract   Multiauthority ciphertext policy attributebased encryption (CPABE) is one of the promising approaches where multiple authorities issue and manage various attributes to achieve finegrained access control on stored data in cloud platforms. However, the practical use of multiauthority CPABE (MCPABE) requires satisfaction of different features. Firstly, in MCPABE, users having the same set of attributes must share the same decryption privileges. This may potentially lead to exposure of decryption keys by some malicious users. Thus, there is a need of designing MCPABE with traceability to overcome this problem. Secondly, as the cost of decryption increases with the complexity of access policy, it is preferred to provide the functionality of outsourcing decryption to reduce the computational burden on the user. Finally, the data owners must have flexibility to change the access policy. Hence, policy updation must be an integral part of MCPABE scheme. In this paper, we construct a new multiauthority CPABE scheme over large attribute universe with decentralization of authorities that supports whitebox traceability along with policy updation and outsourcing decryption. Our proposed cryptosystem is built on prime order groups and supports monotonic access structures. These features improve efficiency and expressiveness of our system. We implemented our proposed cryptosystem in Charm cryptographic framework and analyzed its performance with a diverse set of test cases.