International Journal of Computational Intelligence and Information Security, March 2012 Vol. 3, No. 3 42 Research Challenges and Security Issues in Cloud Computing R. Kalaichelvi Chandrahasan, S Shanmuga Priya and Dr. L. Arockiam AMA International University, Kingdom of Bahrain M.I.E.T Engg College, Tiruchirappalli, India St. Joseph's College, Tiruchirappalli, India kalai_hasan@yahoo.com, shanmugapriyaraj@yahoo.com, larockiam@yahoo.co.in Abstract Cloud computing is a promising computing standard where computing resources in large data center are made available as services over Internet. Cloud computing has become prominent IT by offering the business environment data storage capacity. This new profitable paradigm for computing is an attractive, massive, large- scale investment that includes any subscription-based or pay-per-use service over the Internet. It is on-demand access to virtualized IT services and products. Salesforce, Amazon and Google are currently providing such services, charging clients using an on-demand policy. As the users deal their sensitive data to clouds i.e. public domains, the major hurdles for cloud adoption are lack of security and access control. The main setback is that the insecure information flows as service provider can access multiple virtual machines in clouds. So it is necessary to build up proper security for cloud implementation. The aim of this paper is to provide an overall view of cloud computing with the aim to highlight the possible security issues and vulnerabilities connected with virtualization infrastructure. Keywords: Cloud Computing; Virtualization; On-Demand Policy; Security; Service Provider; Public Domains 1. Introduction Cloud computing takes virtual infrastructure and builds upon research in distributed computing, grid computing, utility computing, autonomic computing, networking, web services and software services. It has shown tremendous potential to empowerment, agility, multi-tenancy, reliability, scalability, availability, performance, security and maintenance. Through Cloud environment Email, Instant messaging, business software, and web content management can be offered. It incorporates many existing technologies such as information and infrastructure consisting of pools of computers, networks, distributed services application, information and storage resources. The US National Institute of Standards and Technology (NIST) defines cloud as follows: “Cloud computing is a model for enabling convenient, on-demand network access to a shared pool of configurable computing resources (e.g., networks, servers, storage, applications, and services) that can be rapidly provisioned and released with a minimal management effort or service provider interaction. This cloud model promotes availability and is composed of five essential characteristics, three delivery models, and four deployment models.” [1]. Due to the ever growing interest in cloud computing, we focus on issues that are specific to cloud environment. The rest of this document is organized as follows. Section 2 describes an overview of Cloud that embraces the characteristics of cloud computing, service models, deployment models and cloud scalability. Section 3 presents the security challenges in cloud and the seven layers on the basis of CSA followed by the Service Level Agreement and widely used languages for describing web services in Section 4. Finally, Section 5 concludes the paper and discusses the future work. 2. Cloud: Overview 2.1 Characteristics of Cloud Computing The five characteristics of cloud computing embrace on-demand self-service, ubiquitous network access, location independent resource pooling, rapid elasticity, and measured service [6]. 2.2 Service Models There are three layers referred as delivery models that provide the resources to the clients.