Attribute-Based Inner Product Functional Encryption in Key-Policy Setting from Pairing

Cloud computing is becoming more and more popular among enterprises for high performance, accessibility from any device, removing hardware and software dependencies and cost savings. However, shifting sensitive information and infrastructure from trusted domain to public cloud often leads to privacy concerns and security threats in sectors like medical and finance. Functional encryption (FE) with access control is a promising cryptographic technique playing an important role in fine-grained handling of encrypted data as well as preventing unauthorized access to encrypted data. Key-policy attribute based inner product functional encryption (KP-ABIPFE) is a specific technique that enables sender to encrypt message with respect to attributes and embeds access policy into secret-keys with the aim that only a specific class of recipients would be able to obtain inner product on encrypted data they need for their designated tasks. In this work, we provide an instantiation of KP-ABIPFE based on simple and well-studied pairing based subgroup decisional assumptions in composite order bilinear groups. Our design uses dual system encryption technique of Waters from Crypto 2009. Our scheme performs significantly better in terms of communication overhead compared to the previous similar schemes in bilinear setting.