Most cryptocurrencies are based on blockchain. For example, in Bitcoin, all miners work together to create a sequence of blocks, each of which contains a valid solution to a SHA-256 crypto-puzzle. Each block contains a certain amount of Bitcoin transactions and the history of all blocks are considered as the public legder. As cryptocurrencies get more popular, the rate of transactions arriving to the system is exceeding the limit of the blockchain system. As a result, many transactions are "stuck" in the system buffer and suffer from long waiting time even replaced by a new transaction fee. An ideal system would distribute its capacity to different kinds of transactions. However, given the decentralized nature of Bitcoin, it is impossible to interfere the miners’ behavior who se...[ Read more ]

Most cryptocurrencies are based on blockchain. For example, in Bitcoin, all miners work together to create a sequence of blocks, each of which contains a valid solution to a SHA-256 crypto-puzzle. Each block contains a certain amount of Bitcoin transactions and the history of all blocks are considered as the public legder. As cryptocurrencies get more popular, the rate of transactions arriving to the system is exceeding the limit of the blockchain system. As a result, many transactions are "stuck" in the system buffer and suffer from long waiting time even replaced by a new transaction fee. An ideal system would distribute its capacity to different kinds of transactions. However, given the decentralized nature of Bitcoin, it is impossible to interfere the miners’ behavior who select high cost performance transactions only. In this thesis, I propose a randomized transaction broadcast protocol that may solve the problem.