For the enactment of inter-organizational processes, blockchain can guarantee the enforcement of process models and the integrity of execution traces. However, existing solutions come with downsides regarding throughput scalability, latency, and suboptimal tradeoffs between confidentiality and transparency. To address these issues, we propose to change the foundation of blockchain-based process enactment: from on-chain smart contracts to state channels, an overlay network on top of a blockchain. State channels allow conducting most transactions off-chain while mostly retaining the core security properties offered by blockchain. Our proposal, process channels, is a model-driven approach to enacting processes on state channels, with the aim to retain the desired blockchain properties while reducing the on-chain footprint as much as possible. We here focus on the principled approach of state channels as a platform, to enable manifold future optimizations in various directions, like latency and confidentiality. We implement our approach prototypical and evaluate it both qualitatively (w.r.t. assumptions and guarantees) and quantitatively (w.r.t. correctness and gas cost). In short, while the initial deployment effort is higher with state channels, it typically pays off after a few process instances; and as long as the new assumptions hold, so do the guarantees.

翻译：针对跨组织流程的执行，区块链可保障流程模型的强制实施与执行轨迹的完整性。然而现有解决方案存在吞吐量可扩展性不足、延迟问题以及机密性与透明度之间的次优权衡。为解决这些问题，我们提出改变基于区块链的流程执行基础：从链上智能合约转向状态通道——区块链之上的覆盖网络。状态通道允许在链外进行大部分交易，同时基本保留区块链提供的核心安全属性。我们的方案"过程通道"是一种在状态通道上执行流程的模型驱动方法，旨在保留所需区块链特性的同时尽可能降低链上足迹。本文重点研究状态通道作为平台的原则性方法，为实现延迟、机密性等多方向的未来优化奠定基础。我们以原型方式实现该方法，并从定性（关于假设与保障）和定量（关于正确性与Gas成本）两个维度进行评估。简言之，尽管初始部署成本较高，但状态通道通常在数个流程实例后即可实现收益；只要新假设成立，相关保障也可持续实现。