Blockchain technology is apt to facilitate the automation of multi-party cooperations among various players in a decentralized setting, especially in cases where trust among participants is limited. Transactions are stored in a ledger, a replica of which is retained by every node of the blockchain network. The operations saved thereby are thus publicly accessible. While this aspect enhances transparency, reliability, and persistence, it hinders the utilization of public blockchains for process automation as it violates typical confidentiality requirements in corporate settings. To overcome this issue, we propose our approach named Multi-Authority Approach to Transaction Systems for Interoperating Applications (MARTSIA). Based on Multi-Authority Attribute-Based Encryption (MA-ABE), MARTSIA enables read-access control over shared data at the level of message parts. User-defined policies determine whether an actor can interpret the publicly stored information or not, depending on the actor's attributes declared by a consortium of certifiers. Still, all nodes in the blockchain network can attest to the publication of the (encrypted) data. We provide a formal analysis of the security guarantees of MARTSIA, and illustrate the proof-of-concept implementation over multiple blockchain platforms. To demonstrate its interoperability, we showcase its usage in ensemble with a state-of-the-art blockchain-based engine for multi-party process execution, and three real-world decentralized applications in the context of NFT markets, supply chain, and retail.

翻译：区块链技术适用于在去中心化环境中促进多方协作的自动化，尤其在参与者间信任度有限的情况下。交易记录存储于账本中，区块链网络的每个节点均保留其副本。由此保存的操作因此可被公开访问。尽管这一特性增强了透明度、可靠性和持久性，但它阻碍了公共区块链在流程自动化中的应用，因为其违反了企业环境中的典型机密性要求。为解决此问题，我们提出了一种名为“多权限方法实现互操作应用的交易系统”（MARTSIA）的方案。基于多权限属性基加密（MA-ABE），MARTSIA能够在消息部分级别对共享数据实现读取访问控制。用户定义的策略根据认证者联盟声明的参与者属性，决定该参与者能否解读公开存储的信息。尽管如此，区块链网络中的所有节点仍可验证（加密）数据的发布。我们提供了MARTSIA安全保证的形式化分析，并展示了其在多个区块链平台上的概念验证实现。为证明其互操作性，我们将其与一种基于区块链的最先进多方流程执行引擎联合使用，并在NFT市场、供应链和零售三个真实场景的去中心化应用中进行了展示。