Key Aggregate Tagged File Searching(KATFS)

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 proposed schemes are provably secure and practically efficient.