It is a set of control-based technologies & policies adapted to stick to regulatory compliances, rules & protect data application and cloud technology infrastructure. Because of cloud's nature of sharing resources, cloud security gives particular concern to identity management, privacy & access control. So the data in the cloud should have to be stored in an encrypted form. With the increase in the number of organizations using cloud technology for a data operation, proper security and other potentially vulnerable areas became a priority for organizations contracting with cloud providers. Cloud computing security processes the security control in cloud & provides customer data security, privacy & compliance with necessary regulations.

As we all know the data is transferred via the internet, so one of the major concerns is data security. The major points that one should adopt to secure cloud data are:

• Access Control

• Auditing

• Authentication

• Authorization Encryption protects data from being compromised. It helps in protecting data that is being transferred & stored in the cloud. Encryption helps both protect unauthorized access along with the prevention of data loss.

This emergent cloud technology is facing many technological challenges in different aspects of data & information handling & storage.

Some of the challenges are as follows:

Availability & Reliability: A software or hardware fault can affect the cloud environment which can lead to no access to data so data availability plays an important role in cloud environment.

Security & Privacy: The data must be encrypted and privacy of data must be maintained . Data should be securely saved at cloud by high monitoring and regulated access

Interoperability: It is the ability of computer systems or software to exchange and make use of information. so proper interoperability should be maintained within the cloud.

Data Redundancy: Data redundancy is a condition created within a database or data storage technology in which the same piece of data is held in two separate places.

Disaster recovery: An information technology disaster recovery (DR) plan provides a structured approach for responding to unplanned incidents that threaten an IT infrastructure, which includes hardware, software, networks, processes and people.

Data Backup: Data backup is a process of duplicating data to allow retrieval of the duplicate set after a data loss event. Today, there are many kinds of data backup services that help enterprises and organizations ensure that data is secure and that critical information is not lost in a natural disaster, theft situation or other kind of emergency.

Data Replication: Data Replication is the process of storing data in more than one site or node. It is useful in improving the availability of data. It is simply copying data from a database from one server to another server so that all the users can share the same data without any inconsistency.

Data Location: While cloud services appear relatively static to customers, behind the scenes it can be anything but. Once data enters the cloud, it might traverse many different data centers and geographic regions, be hosted multiple places simultaneously or be dynamically relocated as needed.

There are multiple reasons why this can happen. Cloud services providers may move data as a hedge against downtime (i.e., to mitigate localized outages), to reduce latency (by servicing requests closest to the point of origin) or to reduce costs.

Data Fragmentation: Data fragmentation allows you to break a single object into two or more segments or fragments. The object might be a user's database, a system database, or a table. Each fragment can be stored at any site over a computer network. Fragmentation, in the context of a hard disk, is a condition in which the contents of a single file are stored in different locations on the disk rather than in a contiguous space. so in cloud similarly data is fragmented and kept at various geographical regions which increases overhead of keeping tack.

Data Integration: Cloud data integration is the process of configuring multiple application programs to share data in the cloud. In a network that incorporates cloud data integration, diverse applications communicate either directly or through third-party software.

Data Migration: cloud providers must have templates and procedures to migrate data. the loud provider and user should keep in mind the liability concerns, compliances, connectivity concerns

Data Transformation: The data formats needs to be converted to a format that can be used by other cloud applications.

This is data transformation and allows use of data by several cloud applications.

Data Breaches: Data breaches are perhaps the most common threat to cloud databases as reported in the media. In a data breach, hackers gain access to sensitive information stored in the cloud, such as customer credit card numbers or mailing addresses, and use it for personal gain.