A Survey Paper on Key Aggregate Cryptosystem: A Key Assignment Scheme for Scalable Data Sharing Over Cloud Storage

Cloud storage is a model of data storage online in cloud which is accessible from multiple and connected resources, whose demand is greatly increasing. Cloud storage has a requisite functionality i. e. sharing of data securely, efficiently, flexibly over the safe network. Various schemes and methodologies are implemented to make data sharing more effective. Data security is crucial aspect in cloud storage. Providing security to a single file or a set of files is an important factor. With the introduction of encryption and decryption schemes, the storing, sharing and securing of data became rampant. The storing of these ciphertexts and the decryption keys is one of the major issues. There is a need for a mechanism which can minimize the cost of storing these ciphertexts and keys in a secured way. In this era of information, where there is presence of rich data, the true value lies in sharing, securing and storing them. Protecting users data privacy is one of the critical aspects of cloud storage. The survey depicts some encryption schemes introduced in this data privacy for securely and efficient sharing of confidential data over a secure channel. The present research efforts concentrates more on aggregation of these keys into a single aggregate key which will in turn reduce the burden on the network overhead.