摘要
We discuss the problem of accountability when multiple parties cooperate towards an end result,such as multiple companies in a supply chain or departments of a government service under different authorities.In cases where a fully trusted central point does not exist,it is difficult to obtain a trusted audit trail of a workflow when each individual participant is unaccountable to all others.We propose AudiWFlow,an auditing architecture that makes participants accountable for their contributions in a distributed workflow.Our scheme provides confidentiality in most cases,collusion detection,and availability of evidence after the workflow terminates.AudiWFlow is based on verifiable secret sharing and real-time peer-to-peer verification of records;it further supports multiple levels of assurance to meet a desired trade-off between the availability of evidence and the overhead resulting from the auditing approach.We propose and evaluate two implementation approaches for AudiWFlow.The first one is fully distributed except for a central auxiliary point that,nevertheless,needs only a low level of trust.The second one is based on smart contracts running on a public blockchain,which is able to remove the need for any central point but requires integration with a blockchain.
