CIO of a companyThe must impotent points you have to mention in this professional Blog are:1-Intro to problem addressed by this research2-Nature of research process3-Results of research process4- A clear and actionable recommendation addressed to the CIO of a companyAbstract—Cloud computing is the concept implemented toremedy the Daily Computing Problems. Cloud computing isbasically virtual pool of resources and it provides theseresources to users via internet. It offers a range of services forend users; among which there’s Storage as a service. In recentyears, Storage in Cloud gained popularity among bothcompanies and private users. However, data privacy, security,reliability and interoperability issues still have to be adequatelysolved. But the most important problem is security and howcloud provider assures it. In this paper, we have proposed asimple, secure, and privacy-preserving architecture for inter-Cloud data sharing. This architecture is based on anencryption/decryption algorithm which aims to protect thedata stored in the cloud from the unauthorized access.Index Terms— AES, Cloud Storage, cryptography, Datasecurity, Decryption, Encryption, RSAI. INTRODUCTIONLOUD computing is a “new” computer model thatallows using remote services through a network usingvarious resources. It is basically meant to give the maximumcapacity with the minimum resources. The end user has theminimum hardware requirement, but he uses the maximumcapability of computing. This is possible only through thistechnology which requires and utilizes its resources in thebest way. Cloud Computing provides IT services as ondemandservices, accessible from anywhere, anytime and byauthorized user.Recently Storage as a service (STaaS) Cloud gainedpopularity both among private users and companies [1].STaaS is a Cloud business model in which a serviceprovider rents space in its storage infrastructure toindividuals or companies. The data stored in the cloud canbe sensitive to the business. The problematic is that thesedata are likely to be exploited by the provider or otherunauthorized persons. Currently, the most of users of cloudstorage protect their data with SLAs contracts and are basedon the trust and reputation of the provider. This weaknesshas motivated us to think about solutions that enable users tosecure their data to prevent malicious use.Zaid KARTIT, Laboratory of Research in Informatics andTelecommunication (LRIT), University of Mohammed V, Faculty ofSciences, Rabat, Morocco, (e-mail: z_kartit@yahoo.fr).Mohamed EL MARRAKI is with Laboratory of Research in Informaticsand Telecommunication (LRIT), University of Mohammed V, Faculty ofSciences, Rabat, Morocco, (e-mail: elmarrakimohamed@gmail.com).Despite the strengths that represent cloud computing generallyand cloud storage specially; there are a number of researchchallenges such as mobility, interoperability, storage access [3],security, cost, energy efficiency, etc.Security is a major obstacle limiting its spread. There arevarious opinions on the security of cloud computing which dealwith the positives and negatives of it [2].This document is presented as follows: Firstly, it gives acomprehensive definition and the characteristics of cloudcomputing. Secondly, it describes layers and their technologiesrelated to this concept. Thirdly, it describes the different types ofcloud computing and their characteristics. Fourthly, it describesour model proposed of securing data in cloud storage algorithmfor encryption/decryption for outsourcing data in cloud storageand then the general conclusion.II. ABOUT CLOUD COMPUTINGA. DefinitionCloud Computing is an important concept in computerdevelopment in recent years. This concept refers to the use ofcomputing capacity and storage of computers and servers in theworld over the Internet. Cloud services allow individuals andbusinesses to use software and hardware that are managed bythird parties at remote locations. Examples of cloud servicesinclude online file storage, social networking sites, webmail, andonline business applications. Cloud computing provides a sharedpool of resources, including data storage space, networks,computer processing power, and specialized corporate and userapplications.B. Essential CharacteristicsCloud model promotes availability and is composed of fiveessential characteristics[4]:On-demand self-serviceA consumer can unilaterally provision computing capabilities,such as email, applications, and network or server service, asneeded automatically without requiring human interaction witheach service provider.Broad network accessCapabilities are available over the network and accessedthrough standard mechanisms that promote use byheterogeneous thin or thick client platforms (e.g., mobilephones, tablets, laptops, and workstations).Applying Encryption Algorithm to EnhanceData Security in Cloud StorageZaid KARTIT, Mohamed EL MARRAKICEngineering Letters, 23:4, 2015______________________________________________________________________________________________________________________________________________International Association of EngineersISSN: 1816-093X (Print); 1816-0948 (Online)Page 277Resource poolingThe provider’s computing resources are pooled to servemultiple consumers using a multi-tenant model, withdifferent physical and virtual resources dynamicallyassigned and reassigned according to consumer demand.Examples of resources include storage, processing, memory,and network bandwidth.ElasticityCapabilities can be elastically provisioned and released, insome cases automatically, to scale rapidly outward andinward commensurate with demand.Measured serviceCloud systems automatically control and optimize resourceuse by leveraging a metering capability at some level ofabstraction appropriate to the type of service (e.g., storage,processing, bandwidth, and active user accounts). Resourceusage can be monitored, controlled, and reported, providingtransparency for both the provider and consumer of theutilized service.III. LAYERS OF CLOUD COMPUTINGThere are different layers of cloud services that refer todifferent types of service model, each offering discretecapabilities. Apart from management and administration, themajor layers are[2]:A. Infrastructure as a Service (IaaS)Infrastructure as a service delivers computing resources asa service, servers, network devices, and storage disks aremade available to organizations as services on a need-tobasis.Virtualization, allows IaaS providers to offer almostunlimited instances of servers to clients, while making costeffectiveuse of the hosting hardware.Companies can use IaaS to build new versions ofapplications or environments without having to invest inphysical IT assets. Some cloud solutions also rely solely onthis layer like the Amazon’s product EC2, Amazon S3.B. Platform as a Service (PaaS)This layer provides a platform for creating applications.PaaS solutions are essentially development platforms forwhich the development tool itself is hosted in the Cloud andaccessed through internet. With PaaS, developers can buildWeb applications without installing any tools on theircomputers and then deploy those applications without anyspecialized systems administration skills.Examples include Google App Engine, Force.com andMicrosoft Azure.C. Software as a Service (SaaS)This layer includes applications that run off the Cloud andare available on demand to Web and paid for on a per-usebasis, anytime-anywhere basis. There is no need to installand run the special software on your computer if you use theSaaS. A more efficient form is fine grained multi-tenancy [5].The concept of SaaS is attractive and some software runs wellas cloud computing, but the delay of network is fatal to real timeor half real time applications such as 3D online game [6].Examples include online word processing and spreadsheet tools,customer relationship management (CRM) services and webcontent delivery services (Salesforce CRM, Google Docs, etc.).These three are the main layers, although there can also be otherforms of service provided, such as business process as a service,data as a service, security as a service, storage as a service(object of our paper), etc.IV. CLOUD DEPLOYMENTSMODELSA. Private CloudPrivate cloud is a new term that some vendors have recentlyused to describe offerings that emulate cloud computing onprivate networks. It is set up within an organization’s internalenterprise datacenter. In the private cloud, scalable resourcesand virtual applications provided by the cloud vendor are pooledtogether and available for cloud users to share and use. Only theorganization and designated stakeholders may have access tooperate on a specific Private cloud [7].B. Public cloudA public cloud is a model which allows users access to theservices and infrastructure and are provided off-site over theInternet [8]. It’s typically based on a pay-per-use model, similarto a prepaid electricity metering system which is flexible enoughto cater for spikes in demand for cloud optimization. Publicclouds are managed by third parties or vendors over the Internet.Public clouds are less secure than the other cloud modelsbecause it places an additional burden of ensuring allapplications and data accessed on the public cloud are notsubjected to malicious attacks. However, security andgovernance issues must be well planned and ample securitycontrols was put in place.C. Hybrid cloudA new concept combining resources from both internal andexternal providers will become the most popular choice forenterprises. A hybrid cloud is a combination of public andprivate cloud models that tries to address the limitations of eachapproach. In a hybrid cloud, part of the service infrastructureruns in private clouds while the remaining part runs in publicclouds. Hybrid clouds offer more flexibility than both public andprivate clouds. Specifically, they provide tighter control andsecurity over application data compared to public clouds, whilestill facilitating on-demand service expansion and contraction.On the down side, designing a hybrid cloud requires carefullydetermining the best split between public and private cloudcomponents [9].D. Community cloudThis model is rarely offered; the infrastructure is shared byseveral organizations for a shared cause and may be managedinternally or a third party service provider. It brings together, ingeneral, the structures with same interest (mostly security) andmay even be in the same field of activity [10].Engineering Letters, 23:4, 2015______________________________________________________________________________________________________________________________________________International Association of EngineersISSN: 1816-093X (Print); 1816-0948 (Online)Page 278V. SECURITYSecurity in cloud computing involves concepts such asnetwork security, equipment and control strategies deployedto protect data, applications and infrastructure associatedwith cloud computing. An important aspect of cloud is thenotion of interconnection with various materials whichmakes it difficult and necessary securing theseenvironments. Security issues in a cloud platform can leadto economic loss, also a bad reputation if the platform isoriented large public and are the cause behind the massiveadoption of this new solution. The data stored in the cloudfor customers represents vital information. This is why theinfringement of such data by an unauthorized third party isunacceptable. There are two ways to attack data in Cloud.One is outsider attack and the other is insider attack. Theinsider is an administrator who can have the possibility tohack the user’s data. The insider attack is very difficult to beidentified. So the users should be very careful while storingtheir data in cloud storage. Hence, the need to think ofmethods that impede the use of data even though the data isaccessed by the third party, he shouldn’t get the actual data.So, all the data must be encrypted before it is transmitted tothe cloud storage [11].Security allows the confidentiality, integrity, authenticityand availability of information. The development oftechnologies and their standardization makes available a setof algorithms and protocols for responding to these issues.A. ASYMMETRIC ENCRYPTIONAsymmetric cryptography is a class of cryptographicalgorithms which requires two separate keys, one of which issecret (or private) and one of which is public. Althoughdifferent, the two parts of this key pair are mathematicallylinked. The public key is used to encrypt plaintext or toverify a digital signature; whereas the private key is used todecrypt cipher text or to create a digital signature. In ourpaper we used RSA algorithm through its robustness.RSA AlgorithmThe most common Public Key algorithm is RSA, namedfor its inventors Rivest, Shamir, and Adelman of MIT. RSAis basically an asymmetric encryption/decryption algorithm.Public key distributed to all through which one can encryptthe message and private key which is used for decryption iskept secret and is not shared to everyone. It based onexponentiation in a finite field over integers modulo a primenumbers.RSA uses Euler’s Theorem: ????Ø(????)mod(n) = 1 wheregcd(a,n)=1 in RSA we have to initially calculate n=p.q suchthat Ø(????)=(p-1)(q-1) one has to carefully chose e and d to beinverses mod ø(n).To encrypt a message M we have to obtain public key ofrecipient Pu={????, ????} to calculate the cipher: C=????????mod(n),where 0=M