Public versus Private Blockchains – Part 2: Permissionless Blockchains

Blockchain-based solutions are one of the major areas of research for financial institutions and in other applications across the globe. There is currently an ongoing debate whether the existing blockchain-based systems (such as Bitcoin and other cryptocurrencies) can be utilized as is in proprietary contexts,and whether their openness and censorship resistance are fitting properties in this case. We provide arguments for the use of permissionless blockchains and open blockchain protocols in creating ledgers and registries,devoting particular attention to the Bitcoin blockchain as the most commercially successful and secure permissionless blockchain. We study potential applications of permissionless chains in proprietary environments,such as colored coins,peer-to-peer payment channels and transaction processing by known validators.