  Reflow is a novel signature scheme supporting unlinkable signatures by
multiple parties authenticated by means of zero-knowledge credentials. Reflow
integrates with blockchains and graph databases to ensure confidentiality and
authenticity of signatures made by disposable identities that can be verified
even when credential issuing authorities are offline. We implement and evaluate
Reflow smart contracts for Zenroom and present an application to produce
authenticated material passports for resource-event-agent accounting systems
based on graph data structures. Reflow uses short and computationally efficient
authentication credentials and can easily scale signatures to include thousands
of participants.
