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 implemented our approach prototypically 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：对于跨组织流程的执行，区块链能够保障流程模型的强制执行以及执行轨迹的完整性。然而，现有解决方案在吞吐量可扩展性、延迟以及机密性与透明度之间的次优权衡方面存在缺陷。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——一种建立在区块链之上的覆盖网络。状态通道允许在链下进行大多数交易，同时基本保留区块链提供的核心安全属性。我们的方案——流程通道——是一种基于模型驱动的方法，用于在状态通道上执行流程，旨在保留所需的区块链特性，同时尽可能减少链上占用。本文重点研究状态通道作为平台的原则性方法，以便未来在延迟和机密性等多个方向进行大量优化。我们以原型方式实现了该方法，并进行了定性（关于假设和保障）和定量（关于正确性和Gas成本）评估。简而言之，尽管使用状态通道的初始部署成本较高，但在执行少量流程实例后通常即可获得回报；只要新的假设成立，保障措施也同样成立。