Internet-Draft alfa-authz July 2024
Brossard, et al. Expires 23 January 2025 [Page]
Workgroup:
Web Authorization Protocol
Internet-Draft:
draft-brossard-alfa-authz-00
Published:
Intended Status:
Standards Track
Expires:
Authors:
D. Brossard
Axiomatics
A. Clymer
Rock Solid Knowledge
T. Dimitrakos
University of Kent School of Computing

ALFA 2.0 - the Abbreviated Language for Authorization

Abstract

The Abbreviated Language for Authorization 2.0 is a constrained policy language aimed at solving fine-grained authorization challenges. This specification builds on top of [XACML] and replaces [ALFA] to provide a more complete and easier language to use.

Use cases for ALFA 2.0 include the ability to express: - Role-based access control ([RBAC]), - Attribute-based access control ([ABAC]), and - Relationship-based access control ([ReBAC])

About This Document

This note is to be removed before publishing as an RFC.

The latest revision of this draft can be found at https://davidjbrossard.github.io/alfa-authorization-language/draft-brossard-alfa-authz.html. Status information for this document may be found at https://datatracker.ietf.org/doc/draft-brossard-alfa-authz/.

Discussion of this document takes place on the Web Authorization Protocol Working Group mailing list (mailto:oauth@ietf.org), which is archived at https://mailarchive.ietf.org/arch/browse/oauth/. Subscribe at https://www.ietf.org/mailman/listinfo/oauth/.

Source for this draft and an issue tracker can be found at https://github.com/davidjbrossard/alfa-authorization-language.

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This Internet-Draft will expire on 23 January 2025.

Table of Contents

1. Introduction

While authentication has largely been solved and standardized (see [OAUTH] and SAML as successful authentication standards), not as much can be said of authorization. One of the oldest and more mature standards is [XACML], the eXtensible Access Control Markup Language established in 2001 under the helm of OASIS. The latest version, XACML 3.0, was released in 2013.

Since, there has been little innovation in the authorization space. Two standards emerged:

While OPA became part of CNCF, ALFA remained as a draft under OASIS. OPA's strength is also its drawback. It's a fullblown Datalog-based programming language which can achieve anything: it's extremely broad. As for ALFA, as mentioned above, it's true to XACML and aims to achieve lossless round-trip translations leading to unnecessary complications in ALFA's existing grammar.

The aim of this standard is to provide a simple and constrained authorization language largely inspired by ALFA but not tied to XACML and not limited by the need to provide round-tripping.

2. Conventions and Definitions

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 [RFC2119] [RFC8174] when, and only when, they appear in all capitals, as shown here.

3. Security Considerations

TODO Security

4. IANA Considerations

This document has no IANA actions.

5. References

5.1. Normative References

[ABAC]
Hu, V. and D. Ferraiolo, "Guide to Attribute Based Access Control (ABAC) Definition and Considerations - NIST Special Publication 800-162", , <https://doi.org/10.6028/NIST.SP.800-162>.
[ALFA]
Giambiagi, P., Nair, S. K., and D. Brossard, "Abbreviated Language for Authorization Version 1.0", , <https://groups.oasis-open.org/higherlogic/ws/public/download/55228/alfa-for-xacml-v1.0-wd01.doc>.
[RFC2119]
Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, , <https://www.rfc-editor.org/rfc/rfc2119>.
[RFC8174]
Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, , <https://www.rfc-editor.org/rfc/rfc8174>.
[XACML]
Rissanen, E., "eXtensible Access Control Markup Language (XACML) Version 3.0, OASIS Standard", , <https://docs.oasis-open.org/xacml/3.0/xacml-3.0-core-spec-os-en.html>.

5.2. Informative References

[OAUTH]
Hardt, D., Ed., "The OAuth 2.0 Authorization Framework", RFC 6749, DOI 10.17487/RFC6749, , <https://www.rfc-editor.org/rfc/rfc6749>.
[OPA]
Styra, "Open Policy Agent | Documentation", , <https://www.openpolicyagent.org/docs/latest/>.
[RBAC]
Kuhn, R., Ferraiolo, D., and R. Sandhu, "The NIST Model for Role-Based Access Control: Towards a Unified Standard", , <https://doi.org/10.1145/344287.344301>.
[ReBAC]
Gates, C., "Access Control Requirements for Web 2.0 Security and Privacy", , <https://doi.org/10.1145/344287.344301>.

Acknowledgments

The authors would like to acknowledge the authors of the original version of ALFA namely Pablo Giambiagi and Dr. Srijith Nair. The authors would also like to acknowledge Erik Rissanen, the then editor of the XACML Technical Committee.

Authors' Addresses

David Brossard
Axiomatics
Canada
Andrew Clymer
Rock Solid Knowledge
United Kingdom
Theodosios Dimitrakos
University of Kent School of Computing