Privacy Preserving and Information Sharing in Decentralized Online Social Network

Online Social Networks are most widely used services these days. Many popular online social networks are logically centralized systems. Central providers aggregate substantial information i.e., sensitive personal data which is intrinsic threat to the privacy of the users. To this extent, the concept of Decentralized Online Social Networks has been provoked. Instead of keeping data at the single provider, data is spread out across multiple servers or is distributed completely among user devices that is from a peer-to-peer network. The difficulty of sustaining the privacy of the contents shared to the large groups of users will be focused in this paper. In general, encryption is prescribed on content for its privacy and secrecy, and only authorized parties will be able to perform decryption over content. New explications have to be improvise, when performance has to be seized that:
$i)$
when the composition of the group changes, the re-encryption of the contents published in a group should be shortened, and
$ii)$
improve the group sharing scheme such that there will be no need to change corresponding keys in case of any changes occur in group i.e., addition or removal of group member. Current solutions fall short in meeting the above criteria, while our approach will be requiring only onetime encryption operation for every file. In our proposed system, there is no need to change or update keys when a user is removed from a group or joins the group.