Security and Privacy Preserving of Shared Data on Cloud

Cloud computing is a prominent emerging data interactive prototype, which helps in storing data online over cloud servers. The vital objective of cloud computing is to ensure the services provided by group of networked elements need not be individually managed or addressed by users. Instead, the entire provider-managed suite of software and hardware can be thought of as a nebulous cloud. To provide privacy and security to data of individual users is obvious but to share the data between group of users along with ensuring privacy and security is a challenging task. Since in organizations, data sharing may be a collaborative approach, thus sharing of the data becomes more important to achieve the goals. Providing security to data over the cloud becomes hectic as data may be accessed by group members. Therefore, the need is to focus on the authentication provided to access data. Cloud security refers to a wide variety of technologies, applications, policies and controls utilized to protect data, applications, virtualized IP, services, and the analogous infrastructure of cloud computing. To overcome the issue of privacy and authentication, data access permissions are assigned. This project is focused towards the data access permissions based on public or private data. If the data is private, then it is cryptographically handled as the file is encrypted before it gets uploaded to cloud server and for authorized user it gets decrypted and downloaded upon OTP validation. The encryption and decryption algorithms are the enhancement of hill-cipher algorithm. This enhancement is based on time taken to encrypt the data with respect to size of the file. Hence the accuracy and efficiency of these algorithms are found to be higher than the legacy hill-cipher algorithms.