Supernova: Super-peers based architecture for decentralized online social networks

Abstract. Recent years have seen several earnest initiatives from both academic researchers as well as open source communities to implement and deploy decen-tralized online social networks (DOSNs). The primary motivations for DOSNs are privacy and autonomy from big brotherly service providers. The promise of decentralization is complete freedom for end-users from any service providers both in terms of keeping privacy about content and communication, and also from any form of censorship. However decentralization introduces many challenges. One of the principal problems is to guarantee availability of data even when the data owner is not online, so that others can access the said data even when a node is offline or down. Intuitively this can be solved by replicating the data on other users ’ machines. Existing DOSN proposals try to solve this problem using heuristics which are agnostic to the various kinds of heterogeneity both in terms of end user resources as well as end user behaviors in such a system. For instance, some propose replication at friends, or at some other peers based on other heuris-tics such as reciprocal storage among nodes with similar availability, or storag