Secure sharing of health data over cloud

Modern information technology is increasingly used in healthcare with the goal to improve and enhance medical services and to reduce costs. In this context, the outsourcing of computation and storage resources to general IT providers (cloud computing) has become very appealing. As cloud computing is becoming more mature data outsourcing in public cloud is also gaining momentum including sensitive information like personal data, health data, media files and government documents. For sensitive data which is outsourced in public cloud, its encrypted uploads are recommended thus narrowing its utility scope in terms of processing and evaluation. To evaluate user requests obliviously on public cloud over sensitive encrypted data, we have formalized a system which protects not only the privacy of data but also the evaluation process that is carried on the public cloud. Throughout the system execution the cloud server will learn nothing useful except the reply cardinality.