A Model for Signatories in Cyber-Physical Systems

Abstract

Distributed Internet of Things and cyber-physical systems can potentially be used as agents to automatically sign events and transactions on behalf of users. To accomplish this, there is a need for a model that can represent the relationships, credentials and organizational hierarchies of people and devices, facilitating agents acting as signatories in a controlled way. This paper proposes such a model, where people in different positions are entitled to sign on behalf of organizations or departments therein and extend that to representing machines. Central in this model is the Power of Attorney (PoA), which is a self-contained and signed digital document that for a limited time and in a defined context, authorizes a particular agent (whether a person or device) to sign on behalf of a principal. Although such selfcontained PoAs can be stored anywhere, we propose a conceptual architecture based on PoAs and include a signatory registry that keeps track of organizational hierarchies in terms of people and devices according to the defined model and stored PoAs in that context.

Multilevel Subgranting by Power of Attorney and OAuth Authorization Server in Cyber–Physical Systems

“…PoA-based authorization [8] is an authorization technique used to authorize devices to access protected resources on behalf of the principal, without requiring the principal to be online. The PoA model in its base form is completely decentralized (like for example Pretty Good Privacy (PGP)), where the user subgrants their power in the form of a selfcontained PoA that contains public information such as public keys and a specific set of permissions for a predefined time.…”

“…The scope of this paper is to compare existing delegation models, specifically the Power-of-Attorney (PoA) [8], the proxy signature by warrant [9], and OAuth [6]. The objective is to analyze the trade-offs and propose a solution based on industry standards to facilitate industry uptake.…”