Dynamic Role Authorization in Multiparty Conversations

Abstract

Protocol specifications often identify the roles involved in communications. In multiparty protocols that involve task delegation it is often useful to consider settings in which different sites may act on behalf of a single role. It is then crucial to control the roles that the different parties are authorized to represent, including the case in which role authorizations are determined only at runtime. Building on previous work on conversation types with flexible role assignment, here we report initial results on a typed framework for the analysis of multiparty communications with dynamic role authorization and delegation. In the underlying process model, communication prefixes are annotated with role authorizations and authorizations can be passed around. We extend the conversation type system so as to statically distinguish processes that never incur in authorization errors. The proposed static discipline guarantees that processes are always authorized to communicate on behalf of an intended role, also covering the case in which authorizations are dynamically passed around in messages.Comment: In Proceedings BEAT 2014, arXiv:1408.556

A Calculus for Modeling Floating Authorizations

“…We left out non-determinism in the form of choice since our focus is on the interplay between parallel composition and authorization scope, and we believe adding choice to our development can be carried out in expected lines. We remark that in [7] a certain form of accounting inconsistency when handling authorization delegation was already identified, while in this work we believe accounting is handled consistently throughout the model. We intend to study the behavioral theory of our model, also for the sake of illuminating our notion of floating authorizations and their accounting, where for instance an axiomatization of the behavioral semantics would surely be informative on the authorization scoping construct.…”

“…We have presented a model that addresses floating authorizations, a notion we believe is unexplored in the existing literature. We based our development on previous work [7] by extending the model in a minimal way so to carry out our investigation, even though the required technical changes revealed themselves to be far from straightforward. We left out non-determinism in the form of choice since our focus is on the interplay between parallel composition and authorization scope, and we believe adding choice to our development can be carried out in expected lines.…”

“…In this section we present our process model, an extension of the π-calculus [12] with specialized constructs regarding authorizations adopted from a model for authorizations [7]. The syntax of the language is given in Table 1.…”

A Typed Model for Dynamic Authorizations

“…The work presented here builds on our previous work [7], in which we explored authorization passing in the context of communication-centered systems. In [7], the analysis addressed not only authorization passing but also role-based protocol specification, building on the conversation type analysis presented in [2].…”

“…Even if the teller gained access to the communication medium when joining the interaction, the authorization to act on behalf of the bank portal may not be necessarily granted; in such cases an explicit mechanism that dynamically grants such an authorization is required. To account for this kind of scenarios, in previous work [7] we explored the idea of role authorizations. It appears to us that the key notions underlying this idea can be well explored in a more general setting; here we aim at distilling such notions in a simple setting.…”