The Road to Scalable Blockchain Designs

Bitcoin has become centralized and slow due to the inherent limitations of its blockchain. A number of alternative blockchain designs have been proposed to address these issues. Off-chain solutions allow for small and frequent transactions to take place over low-tier blockchain instances, parallel to and backed by the main blockchain. On-chain solutions directly modify the blockchain design to support high performance. We focus on the latter and summarize and discuss recent approaches to on-chain scaling of blockchains.