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A Comprehensive Study of the Cloud Computing Technology
Ibrahim
Author’s Group no.03, Student no.201, e-mail:
Master of Management information system
Abstract: Cloud computing relies on the internet to provide processing resources and information to computers and other devices when required. The technology allows users to process and store information on a third party server which may be located in the local area or some foreign land. Since the users access these services remotely though the Internet, they get information at their fingertips round the clock and are unaware of the location the information is coming from. Although with cloud computing, the companies can focus on business matters rather than setting up and managing an IT infrastructure, since the company’s data is stored on a third party server, it can be hazardous in cases where the information is confidential. Furthermore, cloud computing allows restricted access to management and control of the data, services and applications. This research paper aims at finding out how cloud computing works; the challenges faced when using cloud computing system, pros and cons of cloud computing technology and the possible solutions to the issues.
Key Words: data server; cloud computing; privacy; confidentiality
1 Introduction
According to a survey by IDG Enterprise Marketing (2015), the trend of organizations adopting cloud computing technology has increased over the years. And this trend will continue to rise in the future as well.

Over 72% of the organizations have at least one application hosted in the cloud. The umbrella term ‘cloud computing’ refers to the computing resources that are used for providing independent location services (software, hardware, data storage, data security, etc.) over the Internet. These services can be availed from anywhere in the world by paying to the cloud vendors as per organization’s needs.
Cloud computing allows various organizations to focus on the main aim of the business rather than investing a lot of time and capital on setting up and managing infrastructures. Furthermore, since the Internet technology has become fast, cloud computing save a lot of organizations time in carrying out various shared data related activities within the organization (Alani, 2016, p.68). The organizations can setup an advanced IT infrastructure with a minimal startup investment without having to arrange for the human and physical resources, generally involved in the installation, maintenance and upgrade of the IT infrastructure. Organizations can start small and dynamically increase their resources as per their service needs (Nayab, 2011; Shawish and Salama, 2014).
Having proven to be a promising technology, cloud computing will become a need of the standalone or collaborative organizations in future (Shawish and Salama, 2014). So, it is important to understand the basic architecture of cloud computing, how the technology works, its effects on an organization’s operations and costs, its pros and cons. This paper aims to shed light on all these aspects of the cloud computing technology.
1.1 Background Information
In the past, before the Internet, the simple daily life activities such as communication, financial transfers, etc. were very time-consuming. These tasks involved a lot of traveling which was dependent on the state of transport technology of the time. As the various communication technologies developed, the pressure on people in carrying out these daily activities reduced. For example, before the development of western union money transfer technology, people could not send or receive money from the overseas. Therefore, one could not get money unless he/she personally traveled to the particular foreign country. And besides using a lot of capital to carry out the various activities, the process could take a lot of time and be very tiresome. Additionally, one could come across unplanned events, some of which may not be budgeted for e.g. a road accident when traveling to the bank to withdraw money (Ballantine, 2012, p.89).
The introduction of cloud computing has enabled people to save a lot of time, money and resources. It has also ensured that people do not lose their valuable information when their devices (e.g. laptops and phones) get lost and that the people have access to their data from anywhere in the world at all times. This is because the data is safely stored at a place which can be easily accessed through the Internet.
Statement of the problemStandalone companies, collaborative research organizations and individuals all over the world are making efforts to embrace cloud computing technology and adapt to the ever-changing digital life. Individuals usually join a cloud computing site under the influence of their social circles. For instance, their friends often visit or use the site or someone from the social circle might have recommended it, etc. Many of these users are unaware of the underlying technology involved in running these sites and how the information is stored and retrieved. They are unaware of how they should ensure their safety while joining these sites. The same applies to various companies and organization that sought out to start a cloud service just for the sake of embracing the technology and being in pace with the technology trend. But as they progress in providing the cloud services, they are posed with different challenges (Bento and Aggarwal, 2013, p.67).
One of the challenges in cloud technology is the security of the information or data that the individuals or organizations store and the transactions they make over the Internet. Some of such activities may require the uploading of photos of the individuals or other personal information. This sharing of confidential information, at times, lead to insecurities and vulnerabilities as people get tracked and kidnapped especially if they have been involved in several high capital transactions (Furht, and Escalante, 2010, p.201). The various problems encountered while using the cloud computing technology has raised the concern of how to mitigate the issues of cloud technology.
Research questionsSince this paper aims to provide a comprehensive overview of the cloud technology, the research questions to investigate are as follows;
What is cloud computing?
What are the security challenges of cloud computing?
What are the weaknesses of cloud computing?
What are the solutions to the cloud computing challenges?
2 Literature Review
The origin of using the symbol of the cloud for representing the Internet can be traced back to the old software programs that were used to draw internet diagrams. These diagramming programs represented the servers with circular edged icons and the numerous networked devices with overlapped circles. In 1994, the symbol of cloud was used for representing distributed computing platforms.
The art of sharing dates back to the 1970s when the Remote Job Entry was used by big vendors such as IBM and DEC. Later on, Multics, UNIX port, and Cambridge CTSS platforms replaced Remote Job Entry by offering full-time sharing, which was not previously provided. In the 1990s, some companies which used to provide telecommunication services started providing virtual private network services, and that too at a reduced cost. They began using the symbol of a cloud to represent the boundary between the responsibility of the user and that of the service provider (Buyya et al., 2011, p.60).
With time, the demarcation of cloud computing expanded and started including all of the network facilities and servers. And as the exposure of people to computer increased and a number of users rose, the concept of time sharing was introduced to allow availability of computing power and resources to all individuals accessing the common resources. Cloud computing came into existence in the early 2000s. It was first utilized by the European Commission funded project that used the hybrid and private clouds. (Jaatun et al., 2009, p.187). Later on, efforts were made to ensure that a good quality service is provided to the cloud computing users.
By mid-2008, the cloud computing technology was introduced to and implemented by many IT consumers who sold and bought the cloud-based applications and services. Since then, cloud computing underwent a series of evolution and got embedded into online systems to the extent that now people opt to use it even without having any technical knowledge of it. Presently, over 72% of organizations have at least one company application that is offered to its users through the cloud (IDG Enterprise Marketing, 2015).
Clouds are classified according to their deployment models and offer different types of services. The key technologies underlying cloud technology are virtualization and web services (Shawish and Salama, 2014). The major advantages of virtualization-based cloud technology are scalability and resource availability. As cloud technology democratized and came into the use of everyone, organizations and individuals started storing sensitive data on the cloud. As private data found a storage place in the shared data servers, major security concerns related to the technology started to surface. Another concern appeared due to the fact that in a cloud environment, the customers faced a partial or complete loss of control related to cloud configuration and data access. Each of the three cloud computing service types offered a different governance for data and environment control. Concerning data protection, since the cloud technology cannot audit or monitor the cloud activity or maintain log files on the virtual servers, an organization availing the cloud service cannot prove that the cloud operations are in compliance with organization rules (Kelly, 2011).
The relation between the cloud service provider and the cloud client is governed by the Service Level Agreement (SLA). As the number of cloud users increased and the cloud technology became an essential utility of present times, it became crucial to devise a system to determine the correct prices for both the service providers and customers. As organizations and individuals are embracing the cloud technology, it is important that they understand the aspects of cloud technology related to clients i.e. the SLAs, service cost and prices and the issue of security and privacy (Shawish and Salama, 2014).
3 Methodology and Research Design
The research methods and design for the investigative study were based on the secondary data sources from the cloud computing literature which includes some recent journal publications and conference papers on the cloud computing technology that outline its architecture, platforms and applications, security issues and implementation challenges and the proposed solutions.
4 Results and Discussion
The remaining paper provides an overview of the cloud computing technology based on the research findings with a view to the research questions listed previously.
4.1 Cloud Computing Technology
Cloud computing is kind of computing technology that depends on the Internet to provide processing resources and information to computers and other devices when required. Cloud computing and storage technology allows its users and client companies (of different application fields e.g. finance, healthcare, scientific research, transport, military, security, etc.) to keep and process their information by storing it on a third party data and application server which may be located at a local, remote or even a foreign country with reference to the user’s location (Carstensen et al., 2012, p.107).
Cloud computing has enabled various companies and organizations to escape the up-front IT facility costs. So instead of investing considerable amounts of money and time on computer services, companies can focus on their primary objective of promoting and expanding their business. The growth of cloud computing technology was facilitated by the fact that there was the availability of computers which were less costly, had the right capacity network and increased adoption of autonomic, hardware virtualization, etc. (Jaatun et al., 2009, p.87).
4.1.1 Uses of cloud computing technology
Cloud computing technology is used for providing creating new services and applications, recovery, storage and backing up of data, hosting blogs and websites, audio and video streaming, delivery of a demanded software and analyzing data to make predictions and patterns.
4.1.2 Features of cloud computing technology
Cloud computing technology has the following characteristics (Erl et al., 2013, p.60; Halpert, 2011, p.96):
Security. Data security is ensured in cloud computing systems. In cloud computing, the data is stored at a central location where the security resources are provided adequately. However, there still may be cases where the kernel’s security may not be enough, and the sensitive data may be mishandled or gets spread across numerous devices and tenant systems. But generally, accessing the security audit logs is impossible by outsiders and an individuals’ data is secure on the cloud.
Reliable. Reliability is increased when using the cloud technology. Cloud computing technology ensures maintaining a backup of data and disaster recovery at less expensive costs. This is because the data stored on the cloud is monitored at several redundant places on cloud provider network.
Cost. Cost is reduced when individuals use cloud computing systems. The money allocated to purchase facilities, such as servers, hardware, software and setting up and running data centers, is utilized on operational activities of an institution, organization or a company.
Productivity. Productivity is increased when using cloud computing. With data on the cloud, multiple users can work on the same data simultaneously, as opposed to waiting for the data to be saved and sent via the email. Time is also saved as data is not re-entered when the fields match.
Location and device independence. As the cloud facilities are off site and are available through the Internet, users can connect to the cloud service through a web browser from anywhere in the world and through any device i.e. laptop, phone, etc.
Speed. Cloud computing services are self-serviced. The cloud server retrieves the needed data only when the individuals demand the data. A significant amount of computer-based resources become available to individuals in a very short period of time. With the increased speed, businesses become more flexible and free from the pressure of planning IT infrastructure.
Flexibility. Cloud computing improves the agility in firms, organizations, and companies as it offers flexibility regarding adding, increasing technological facilities resources and re-provisioning. Furthermore, since the cloud computing infrastructure can be accessed from anywhere, people can work even when traveling.
4.1.3Types of cloud computingCloud computing is typically used in four types of configurations;
Public cloud. A public cloud provides open and unrestricted access to internet services for public use. Generally, public cloud services are free to use. However, the security of applications, storage, etc. in public clouds is generally weak. Google, Amazon Web Services and Microsoft are examples of public cloud providers (Chang et al., 2015, p.80)
Private cloud. A private cloud provides facilities that are exclusively meant for a single company, organization or business only. Private clouds are maintained either internally or through a third party (Rosado, 2013, p.97). Additionally, the private cloud may be hosted from within the organization, or third party service renderers may be employed to host the cloud (Munir, 2016, p.123). The service and facilities of private clouds are maintained within a private network.
Community Cloud. A community cloud is used for sharing facilities between various organizations in a community. Usually, the involved organizations have similar concerns such as jurisdiction, security or compliance. A community cloud may be located and managed internally, externally or by a third party. The cost of community cloud is normally distributed among the individuals or organizations using it thus increasing the potential of cost saving (Chen, 2011, p.173)
Hybrid cloud. The hybrid cloud formed by cloud combination, but the clouds remain separate identities. A hybrid cloud crosses the isolation and boundary of the provider in such a way that it cannot be categorized as public, community or private cloud. Hybrid cloud allows organizations and individuals to extend the basic cloud service through integration, customization, and aggregation with other cloud services (Buyya et al., 2011, p.160). Since the hybrid cloud is composed of two or more different clouds, the organizations may use each cloud for a separate service e.g. the sensitive clients’ data can be stored in a private cloud but interconnected to the public cloud containing the organization’s intelligence application. Factors affecting the adoption of the hybrid cloud include data security, the degree of regulation required by the information, requirements of compliance and the type of applications the organization, company or individuals use (Vacca, 2017, p.160).
Other cloud configurations include Inter-cloud and Multi-cloud. Inter-cloud is composed of interconnected clouds that form a network of clouds. Inter-cloud is used for controlling the operations amongst the public cloud users as opposed to the management of operations between consumers and providers as is the case with a hybrid cloud. Multi-cloud aims to minimize the over-reliance on one cloud vendor. Multi-clouds increase flexibility through the availability of choice and help mitigate disasters.
4.1.4 Cloud computing service modelsThe services offered by the cloud computing technology is based on three service models;
Platform as a Service (PaaS). In this model, the cloud service providers avail computing platforms (such as a web server operating system and database server) to provide developers with a development platform for various applications. The developers are provided with a development toolkit, levels of development and payment and distribution methods. So when using PaaS, the developers can run the software on cloud platform quickly and cheaply without having to purchase the required software and hardware layer (Mather et al., 2009, p.82).
As a solution to data delivery, specialized PaaS applications have been developed. These include data PaaS and integration PaaS. Data PaaS allow the clients to maintain transparency in conjunction with control over the underlying cloud facilities such as network, storage, and servers. Integrated PaaS, on the other hand, ensures that the clients can create, govern and execute integration movement (Rosado, 2013, p.67).
With PaaS, the individuals are not able to control and manage the underlying cloud facilities such as the servers, storage devices, network, and operating systems. The users of PaaS can only manage their own applications and configuration settings.
Software as a Service (SaaS). In this model, the cloud service providers provide access to various software applications and databases. The providers manage the underlying facilities and platforms that run the applications. The cost of SaaS model is based on the user’s usage pattern or a monthly or yearly subscription. To use the SaaS model, the users become the cloud clients. Cloud clients are organizations and people that utilize cloud computing services through networked devices e.g. tablets, desktops, smart phones, and laptops or other devices having Ethernet connectivity. Cloud clients cannot manage the facilities and platforms that run the software application. Therefore, they do not need to install and operate the cloud on their personal computers. This characteristic simplifies the cloud developers’ tasks of application maintenance and support
Infrastructure as a Service (IaaS). Infrastructure as a service refers to the Internet services that hide the cloud clients from facility details such as location, security, etc. Hypervisors such as Xen, Oracle, VMware or Hyper-V are used to operate virtual machines. Many hypervisors in a cloud operating system have machines that support virtual services and can scale these services up or down depending upon the customer requirements. Containers are isolated, secured and managed by Linux kernel technologies such as namespace and Linux c groups. Containerization provides better performance as compared to virtualization. This is because the containers do not overheat in contrast to hypervisors (Ivanov et al., 2013, p.106). Furthermore, the capacity of containers can be set to auto-scale automatically. Computing workload eliminates the situations of over-provisioning while still enabling user-based billing. Additional services provided by the IaaS include object storage, load balancers, file and IP addresses. The cloud providers provide the services as per user demand (Krutz, and Vines, 2013, p.69)
The three models are built on top of each other forming a stack as shown in Fig. 3. Other models used by the cloud computing providers include Serverless Computing and Mobile backend as a service. With the Mobile Backend as a service, the mobile and web apps developers connect their applications to storage and computing services of cloud through the software development kits and application program interfaces. The model provides services such as push notification and user management. Serverless computing model, on the other hand, is a code for execution which the cloud providers use to start and stop virtual machines as per people or organization requirements.

Fig. SEQ Figure * ARABIC 3 Cloud Computing Service Models (Ali, 2014)
4.2 Security Challenges of Cloud Computing As the virtual machines are dynamic and fluid in nature, it is impossible to maintain consistency in information security and allow the information to be audited simultaneously. The ease of cloning and distributing data between actual, physical servers may result in propagating configuration mistakes and creating related vulnerabilities. Security cannot be ensured as long as an individual can identify the site of a virtual machine (Rosado, 2013, p.167).
To ensure efficiencies in the cloud, the virtual machines from different organizations are required to be co-sited on the same physical resource. Although the traditional information security centre model is applied to the cloud location, the physical isolation, and hardware-based safety cannot protect the virtual machines, located on the same server, from attacks. Furthermore, the administrative accessibility is through the Internet as opposed to the controlled and on-premises connection access abiding by the traditional information center model (Samani et al., 2015, p.279)
Since many mobiles users will be accessing business services and information without any cooperating network, the need to place security codes on mobile users and cloud services will increase. When data is stored in an accessible cloud, most organizations and businesses become vulnerable to threats as the data is contained in a single location and can be accessed from any part of the world (Sosinsky, 2011, p.93)
A cloud component that is almost always overlooked but can be used to secure the cloud is to have a failover technology in position. In the case of technology failure, a cloud computing company can only survive if only the non-mission critical applications are rendered offline (Srinivasan, 2014, p.70).
4.3 Solutions to security challenges of cloud computingClouds can be successfully deployed if the security issues are fixed first. Encryption of data before storing it in the cloud is one of the suggested solutions to make the information on the cloud secure. The service providers would allow only the relevant individuals, organizations or companies to be able to access the cloud data. The data access control would be implemented through a heterogeneous data-centric security model comprising of an authentication mechanism, data encryption technique, data integrity and recovery methods and user protection (Rao and Selvamani, 2015).
Before the data is stored in the cloud, the users are asked to confirm storage of backup data and no alterations of file keywords. The hash estimation on file can ensure the contents are not changed. To manage data access, distributed architecture for data access can be used. Credential based policies should be used to identify authorized users. Controlled data access can be allowed through implementing permission as a service. Fine-grained access control policies make the cloud perform resource intensive security tasks while keeping the data secure. For sharing of data on the cloud, a data-driven framework can be crafted. Furthermore, intrusion detection and prevention systems can be deployed to protect the information from the real-time network threats (Rao and Selvamani, 2015).
For the initial network connection point, using a software-defined network would strengthen security in virtual machines and apps. Fine-grained policy can be utilized to allow individuals tailor security facilities within the departments, apps, and network.
4.4 Weaknesses of cloud securityThis section provides an overview of the numerous weaknesses identified in cloud computing technology;
4.4.1 Privacy and security
The cloud computing service provider has the authority to access the information stored in the cloud anytime. The access to the data may either be deliberate or accidental. When the information is accessed, the data may be altered or deleted. This will cause the individuals, companies or organizations to lose their valuable information. Additionally, the cloud providers may share the information with third parties if required without notifying the person or the company owning the information. Moreover, CIOs have become reluctant to give out their information to third parties (Yeluri, and Castro-Leon, 2014, p.110). With the increasing figures of information breach and monetary fines, in conjunction with the loss of good conduct, organizations and companies who have been victims once, refuse to move their data to cloud computing as it is more daunting. Many individuals are not aware of where their data is stored, how well the data is protected from external and internal threats and lastly how an individual can retrieve his or her data that is stored if the need arises (Winkler, 2011, p.287).
4.4.2 Quality of service
One of the major and most important reasons why a business would refuse to move its information and applications to cloud computing system is the quality of the cloud service provided. Organizations, businesses, and companies are of the opinion that the Service Level Agreements (SLA) provided by cloud computing are not convincing enough to run production apps on the cloud. The services being offered are not reliable at all.
4.4.3 Data access
Servers that depend on the cloud are inadequate and inappropriate regarding customer service system. Concerns have always been raised over the ownership of data and the loss of control when data is being moved to the cloud. Additionally, the selection of how and where the information will be stored is the most vital issue.
4.4.4 Accessibility of data and downtime
The access to data, when required, is critical to various companies, organizations or businesses. Data stored in the cloud can only be found through connection to the internet as opposed to a relationship that is local. If in any case, the network connection is weak then the services provided by the cloud will also be down or slow. Hence, the information will be inaccessible. Finally, the cloud facility performance may be influenced by some users, load, and the environment. Therefore, individuals and organizations will always have problems when trying to access the data during unfavourable conditions.
4.4.5 The transition of data towards the cloud:
Cloud providers have always faced problems when trying to determine the most secure and best method move data to the cloud and meet the objectives of various businesses. If the process of data transition is not well handled, it may lead to loss of data, putting the organizations at risk.
4.4.6 Reduced customization
Although cloud computing provides a cost-effective solution for availing IT infrastructure, it has only a few options for customization. Because of these few options, the cloud providers may not be in a position to meet all the legal requirements of people and the organizations. Therefore, companies, organizations, businesses, and individuals need to evaluate the risks of using cloud computing and its importance before adopting the technology.
4.5 Further researchTo ensure a long-lasting successful deployment of cloud-based systems, the major challenges posed by the cloud computing technology i.e. data security, resource availability and management should be explored further as part of the future research (Shawish and Salama, 2014). Furthermore, since the cloud computing technology is dominant in the present IT market and its architecture and the customers are dynamic, there needs to be a change in the way the technology operates. Exploring the possibilities of bringing change to the technology according to customer dynamism would guarantee high-quality services to clients and would eventually bring about an increase in overall profits by service providers as well as consumers.
5 Recommendation and ConclusionCloud computation technology is a dominant technology of the present time with a bright future. IT companies and organizations should consider collaborating with cloud providers to provide effectively, low cost and low complexity services to businesses, companies, organizations, and individuals. When a company aims to increase its growth potential, there is an associated decrease in the required resource capacity. So the company aims to configure the IT facilities with minimum time and cost. Cloud computing technology allows the creation of new apps and services very fast while conversing the time and money resources making them available to invest in other company affairs (Rafaels, 2015).
A cloud computing company should outline clear procedures, rules, and regulation to its stakeholders before entering into a contract of data storage. Furthermore, to ensure that the client’s data is safe and secure, the state holders should be notified as to how the information will be stored within the cloud system and what will be the procedure of data transition to and from the cloud. The cloud computing system should also work towards finding a solution of data retrieval when the organization is small.
The paper has successfully presented a comprehensive overview of the prevailing cloud technology. It has explained the cloud technology and its applications, its features, types and service models. It has also highlighted the security concerns related to the cloud technology and the suggested solutions to overcome the issues. It also lists the weakness associated with the technology and points out the future research area in the domain of cloud computing.
References
Alani, M. M. (2016). Elements of cloud computing security: A survey of important practicalities. Springer
Ali, M. (2014). “What is cloud computing stack,” Mazik Global. Accessed on 30 December 2016 from http://www.mazikglobal.com/blog/cloud-computing-stack-saas-paas-iaas/
Ballantine, R. (2012). Cloud Computing: Security Compliance and Governance. Cork: BookBaby.
Bento, A. M., & Aggarwal, A. (2013). Cloud computing service and deployment models: Layers and Management. Hershey, PA: Business Science Reference.
Buyya, R., Broberg, J., & Gościński, A. (2011). Cloud Computing: Principles and Paradigms. Hoboken, N.J: Wiley.
Carstensen, J., Morgenthal, J. P., & Golden, B. (2012). Cloud Computing: Assessing the Risks. Ely: IT Governance Publishing.
Chang, V., Walters, R. J., & Wills, G. (2015). Delivery and adoption of cloud computing services in contemporary organizations. Hershey, PA: IGI Global.
Chen, R. (2011). “Intelligent computing and information science.” International Conference, ICICIS 2011, Chongqing, China, January 8-9, 2011 :proceedings. Berlin: Springer.
Erl, T., Puttini, R., & Mahmood, Z. (2013). Cloud Computing: Concepts, Technology, & architecture.
Furht, B., & Escalante, A. (2010). Handbook of cloud computing. New York: Springer.
Halpert, Ben. (2011). Auditing Cloud Computing: A Security and Privacy Guide. Wiley.
IDG Enterprise Marketing. (2015). “Cloud Computing Survey 2015”. Tech Insights. Accessed on 25 December 2016 from http://www.idgenterprise.com/resource/research/2015-cloud-computing-study/
Ivanov, I. I., Sinderen, M., Leymann, F., & Shan, T. (2013). Cloud Computing and Services Science: Second International Conference, CLOSER 2012, Porto, Portugal, April 18-21, 2012. Revised Selected Papers. Cham: Imprint: Springer.
Jaatun, M. G., Zhao, G., & Rong, C. (2009). Cloud computing: First International Conference, CloudCom 2009, Beijing, China, December 1-4, 2009: proceedings. Berlin: Springer.
Kelly, D. (2011). “How Data-Centric Protection Increases Security in Cloud Computing and Virtualization.” Security Curve. Accessed on 28 December 2016 https://cloudsecurityalliance.org/wp-content/uploads/2011/11/DataCentricProtection_intheCloud.pdf
Krutz, R. L., & Vines, R. D. (2013). Cloud Security: A Comprehensive Guide to secure cloud computing. Hoboken, N.J: Wiley.
Mather, T., Kumaraswamy, S., & Latif, S. (2009). Cloud security and privacy. Beijing: O’Reilly.
Munir, K. (2016). Security management in mobile cloud computing. Hershey, PA: IGI Global.
Nayab, N. (2011). “The Pros and Cons of Cloud Computing.” Bright Hub. Accessed on 25 December 2016 from http://www.brighthub.com/environment/green-computing/articles/104116.aspx
Rafaels, R. (2015). Cloud computing: from beginning to end.
Rao, R.V. and Selvamani, K. (2015). Data Security Challenges and Its Solutions in Cloud Computing. Procedia Computer Science, Elsevier.
Rosado, D. G. (2013). Security engineering for cloud computing: Approaches and tools. Hershey, Pa: IGI Global
Samani, R., Honan, B., Reavis, J., In Jirasek, V., & CSA (Organization). (2015). CSA guide to cloud computing: Implementing cloud privacy and security. Waltham, MA: Syngress.
Shawish, A. and Salama, A. (2014). “Cloud Computing: Paradigms and Technologies.” F. Xhafa and N. Bessis (eds.), Inter-cooperative Collective Intelligence: Techniques and Applications, Studies in Computational Intelligence 495, Springer-Verlag Berlin Heidelberg 2014
Sosinsky, B. A. (2011). Cloud computing bible. Ind: Wiley.
Srinivasan, S. (2014). Security, trust, and regulatory aspects of cloud computing in business environments. Hershey, PA: IGI Global.
Vacca, J. R. (2017). Cloud computing security: Foundations and challenges. CRC Press. Taylor & Francis Group.
Winkler, V. J. R. (2011). Securing the Cloud: Cloud Computer Security Techniques and Tactics. Burlington: Elsevier Science.
Yeluri, R., & Castro-Leon, E. (2014). Building the infrastructure for cloud security: A Solutions view. Apress.