Abstract
Cloud computing has appeared to be state of the art in the world of Information Technology especially in healthcare systems due to its innovative computing deployment model as a source of utility for users. However, many healthcare organizations are disinclined to adapt cloud computing due to security shortcoming associated with its infrastructure and many of them are still unaddressed. To provide a promising security to cloud computing infrastructure is a key issue, as users have a tendency to store their sensitive and classified medical data with cloud service providers which include the both trusted and un-trusted parties of cloud service providers. This paper addresses the distinguishing features of cloud such as, rapid elasticity, pooling of resources, on-demand services to users, multi-tenancy, third-party rule and its security requirements. Then, it presents the analysis of security concerns of cloud computing for healthcare systems in terms of availability, trust, confidentiality, compliance, integrity and audit. Furthermore, single-cloud is far more vulnerable to failure of service unavailability and malicious insiders and due to this reason it is less popular in healthcare, as medical healthcare systems are concerned about its security. From this notion of security concern an advanced model has emerged; "multi-cloud" also known to be "cloud-of-clouds". This paper also provides an insight of security in single-cloud and multi-cloud and possible security recommendations for healthcare systems, as it has been observed that single-cloud has received more focus from researchers in terms of security vulnerabilities than a multi-cloud environment.