The term cloud computing in the simplest of terms mean computing which is based on internet. In cloud computing data is stored in the form of repository which includes hardware and software resources. Cloud computing provide various services like storage, server and various applications to its users over internet. Virtualization is main concept used in this domain. In virtualization various software are used that separate the data into various virtual devices from which data can be easily accessed by the users. Figure below demonstrate the typical cloud constructed situation.

Cloud Service Models

Cloud computing vendors supply their services through different models. According to National Institute of Standards and Technology (NIST) there are basically three standard models.

• Infrastructure as a Service (Iaas): This platform provides various resources on which user can run the software. It provides virtual machine, storage etc. Iaas model provides scalable services which are easily adjustable. Thus Iaas services are well suitable for the workload that is temporary, experimental and changes randomly.
• Platform as a Service(Paas): Paas provides various application to users which are created using different programming languages. A development environment is provided to the user by the developer. In this model a computational platform is given to the user that include OS, environment to execute programs, databases etc.
• Software as a Service(Saas): Saas provide various applications that are running over the cloud like web based email, interfaces, virtual computers etc. User can access via different devices client interface or via interface created by programming language.

Security In Cloud Computing:

Now-a-days cloud computing is widely used in information technology. Thus security is the main concern in this area. There are various key terms which are used to protect the cloud computing services:

• Data Integrity: It means preserving the correctness of the information from unauthorized modification, deletion of data. Various methods like digital signature, RAID are used to maintain the integrity of the data.
• Data Confidentiality: Confidentiality signifies that individual can access only that information which is meant for him. Confidentiality of the data is an essential issue. To store private information on cloud confidentiality of the data is very important. In order to keep confidentiality, various encryption techniques are used.
• Data Availability: The availability of data means how the data should be recovered and how the client confirm their data in case of any accidents like as damage of hard disk, natural disasters, failure of the whole network etc. In such cases service provider must ensure security as well as confidentiality and integrity of the data. Accurate data should be provided to the user according to their needs.
• Data Privacy: Privacy in cloud signifies that data should not be in direct contact with users. The data should be prevented from unauthorized person by inferring their behavior when they visit the information stored on the cloud. Various protection methods are used to protect the leakage of data and loss of data.

By - Neetu Rani – Asst. Prof. CSE, Chitkara University H.P.

References:-

• M. Ahmed and M. A. Hossain ," Cloud computing and security issues in the cloud", International Journal of Network Security & Its Applications (IJNSA), Vol.6, No.1, January 2014
• http://www.webopedia.com/TERM/C/cloud_computing.html
• Y.Sun, J. zhang,Y. xiong, and G. zhu, "Data Security and Privacy in Cloud Computing"hindawi publishing corporation international journal of distributed sensor networks Volume 2014, Article ID 190903.