Bitcontracts: Supporting Smart Contracts in Legacy Blockchains

In this paper, our main goal is to design a solution that adds expressive smart contract execution support as a subsystem to existing legacy blockchain systems. The primary usage of our solution is to enhance systems like Bitcoin that have no built-in smart contract capabilities. The secondary usage is to extend the contract execution capabilities of platforms like Ethereum that support contracts but have severe limitations on the complexity of allowed computations.