A blockchain is a decentralized peer-to-peer (P2P) ledger system introduced for the Bitcoin cryptocurrency in 2008, and deployed for many other cryptocurrencies. Notable extensions include Ethereum smart contracts, Ripple’s consensus protocol, etc.. A blockchain, permissionless and permissioned, with its decentralized feature and immutable data makes it potentially applicable to numerous scenarios where value or data is transferred/shared, stored and processed. There are two fundamental challenge problems in blockchain technology. One is the scalability in consensus protocols of blockchain networks for updating the ledger which can resist to attacks on P2P network systems (e.g., Sybil attacks, routing attacks, etc.), and the second is how to provide a certain degree of sender/receiver and transaction privacy required for some applications (e.g., banking, heath care, and supply chain management applications), although transaction transparency is the powerhouse of trust in blockchains.
The goal of this research is to investigate attack resistant scalability of consensus protocols and privacy for sender/receiver/transaction in blockchain networks.