Efficient attribute-based encryption with repeated attributes optimization

Internet of Things (IoT) is an integration of various technologies to provide technological enhancements. To enforce access control on low power operated battery constrained devices is a challenging issue in IoT scenarios. Attribute-based encryption (ABE) has emerged as an access control mechanism to allow users to encrypt and decrypt data based on an attributes policy. However, to accommodate the expressiveness of policy for practical application scenarios, attributes may be repeated in a policy. For certain policies, the attributes repetition cannot be avoided even after applying the boolean optimization techniques to attain an equivalent smaller length boolean formula. For such policies, the evaluated secret shares are also multiple for repeated attributes; hence, the ciphertext computed for those irreducible policies is long and computational effort is more. To address this issue, a new CP-ABE scheme is proposed which employs our Repeated Attributes Optimization algorithm by which the Linear Secret Sharing Scheme matrix sent along with ciphertext will contain the access structure of policy including attributes appearing multiple times, but the ciphertext will only be evaluated for unique non-repeated attributes. Security and performance analysis show that the proposed construction fulfils its goals of achieving desired security with low communication overhead and computational cost for resource-constrained devices.