Smart contracts for appendable-blocks blockchain

Abstract

Blockchain has some unique characteristics, such as decentralization in an un- trusted environment, auditability, and security, just to cite a few. Some blockchains can even provide smart contracts , which is the ability to execute code in a distributed manner. This has a tremendous potential to extend the blockchain benefits to any type of applica- tion. However, this concept has not been fully exercised due to the associated challenges of high computational complexity and latency. Those challenges are both associated with smart contracts and blockchain. Some solutions have been developed to try to mitigate those problems. One important work on the blockchain side is the development of the appendable- block blockchain. This type of blockchain has the potential to reduce latency and scalability problems by allowing the parallel addition of data into the blockchain. However, currently, this model lacks the possibility to execute smart contracts. Furthermore, traditional models for smart contracts are not compatible with the appendable-block blockchain. In this work, we present a solution for this shortfall by introducing a model for smart contract execution, which we call the context-based model. This model not only allows appendable-block blockchain to execute smart contract, but also benefits from the parallel nature of the appendable-block blockchain. This increases scalability, by allowing the execution of smart contracts in paral- lel. Those claims are backed up by a proof of concept implemented in this work where the performance is compared to the sequential execution of smart contracts.