Abstract

Now a day’s cloud computing is being used in several areas like industry, medical, science and research, colleges\netc for storage of huge amount of data. User can retrieve data files from cloud data center on request. While storing data files\non cloud server several security issues may arise. Cloud computing has been flourishing in past years thanks to its ability to\nproduce users with on-demand, flexible, reliable, and affordable services. With a concept of cloud applications being offered,\ninformation security becomes a vital issue to the cloud. To overcome from these security issues there are a number of\ntechniques. Out of several security techniques Cryptography is more popular now a day’s for data security. Use of a\ntraditional cryptography algorithm is not effective or sufficient for high level security to data in cloud computing. So, as to\ncreate certain security of data at cloud data storage a design and implementation of an algorithm to enhance cloud security is\nproposed. In this paper we have introduced new security technique based on symmetric key cryptography algorithm and ID\nbased cryptography algorithm. Proposed methodology or system is provides security to data files by using hybrid\nencryption/decryption technique. The hybrid algorithm is designed by using Vigenere algorithm and AES algorithm. Before\nencryption the cloud server generates encrypted key that is to be used to encrypt data files using hybrid algorithm. This\nencrypted key is generated by using concept of ID based encryption algorithm and hash value of secret password allotted to\neach registered user. This encrypted key is of variable size dependent on the data file’s size. For authentication of user SHA-\n512 algorithm is used. As a result the proposed algorithm provides enhanced security as well as reduces time complexity\nduring encryption and decryption process of data file.