Key Aggregated Multiuser File Sharing

Abstract

The important functionality in cloud is a sharing .To address user concerns over potential data leaks in cloud storage a common
approach is for the data owner to encrypt all data before uploading them to the cloud, such that later the encrypted data may be
retrieved and decrypted those who have the decryption keys. A key challenge to designing such encryption schemes lies in the
sufficient management of encryption keys. This also implies the necessity of securely distributing to users a large number of keys
for both encryption in search and user will have to securely store the received key and submit an same large number of keywords
trapdoors to the cloud in order to perform search over the shared data. The practical problem of privacy preserving data sharing
system based on public cloud storage which requires a data owner to distribute a large number of keys to users to enable them to
access his/her documents. By addressing this practical problem which is hugely neglected in literature, we propose the novel
concept of key aggregate Tagged File Searching (KATFS) in which data owner only need to distribute a single to user for sharing
large number of data and user only needs to submit a single trapdoor to the cloud for querying the shared a large number of
documents.
The ability of selectively distributing unreadable data with many users via public cloud storage may greatly ease security concerns
over in advertent data leaks in the cloud. To designing the encryption schemes lies in the efficient management of encryption
keys.The desired flexibility of sharing any group of selected documents with any group of users demands different encryption keys
to be used for different data .The necessity of safely distributing to users a large number of keys for both encryption and search,
and those users will have to securely store the received keys, and submit an equally huge number of keyword trapdoors to the
cloud in order to perform search over the shared data. The required for secure communication, storage, and complexity clearly
renders the approach impractical. The concept of Key Aggregate Tagged File Searching (KATFS) and instantiating the concept
through a concrete KATFS scheme, in which a data owner only needs to distribute a single key to a user for sharing a large
number of documents, and the user only needs to submit a single trapdoor to the cloud for querying the shared documents.The
security analysis and performance evaluation both confirm that our pro-posed schemes are provably secure and practically
efficient.