Authentication and Authorization for Constrained Environments (ace)

WG Name Authentication and Authorization for Constrained Environments
Acronym ace
Area Security Area (sec)
State Active
Charter charter-ietf-ace-01-01 External Review (Message to Community, Selected by Secretariat)
Status Update Show update (last changed 2018-03-22)
Dependencies Document dependency graph (SVG)
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Personnel Chair Daniel Migault 
Area Director Benjamin Kaduk 
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Charter for Working Group

The IETF has recently developed protocols for use in constrained
environments, where network nodes are limited in CPU, memory and power.
REST architecture is widely used for such constrained environments.
It has been observed that Internet protocols can be applied to these
constrained environments, often only requiring minor tweaking and
profiling. In other cases, new protocols have been defined to address
the specific requirements of constrained environments. An example of
such a protocol is the Constrained Application Protocol (CoAP).

As in other environments, authentication and authorization questions
also arise in constrained environments. For example, a door lock has to
authorize the person seeking access using a "digital key". Where is the
authorization policy stored? How does the digital key communicate with
the lock? Does the lock interact with an authorization server to obtain
authorization information? How can access be temporarily granted to
other persons? How can access be revoked? These types of questions have
been answered by existing protocols for use cases outside constrained
environments, however in constrained environments, additional and
different requirements pose challenges for the use of various security
protocols. In particular, the need arises for a dynamic and fine grained
access control mechanism, where clients and/or resource servers are

The IETF has a long history in developing three-party authentication and
authorization protocols for distributed environments. Examples include
Kerberos, the Public Key Infrastructure (PKI), the Authentication,
Authorization and Accounting (AAA) infrastructure, and the Web
Authorization Protocol (OAuth). All these protocols enjoy widespread
deployment on the Internet. Although they all aim to solve a similar
goal, at an abstract level, they offer quite different functions and
utilize different message exchanges. These differences result from the
main deployment use cases they were designed for respectively.

Requirements derived from use cases may indicate that existing work is
useful as basis for a solution for constrained environments. These
protocols, however, were not optimized for constrained environments.
Additional requirements that need to be taken into account are the lack
of a suitable user-interface and the inability of embedded devices to
contact an authorization server in real-time with every resource access
request due to intermittent connectivity, etc.

This working group therefore aims to produce a standardized solution for
authentication and authorization to enable authorized access (Get, Put,
Post, Delete) to resources identified by a URI and hosted on a resource
server in constrained environments. As a starting point, the working
group will assume that access to resources at a resource server by a
client device takes place using CoAP and is protected by DTLS. Both
resource server and client may be constrained. This access will be
mediated by an authorization server, which is not considered to be

Existing authentication and authorization protocols will be evaluated
and used where applicable to build the constrained-environment solution.
This requires relevant specifications to be reviewed for suitability,
selecting a subset of them and restricting the options within each of
the specifications. Some functionality, however, may not be available in
existing protocols, in which case the solution may also involve new
protocol work. Leveraging existing work means the working group benefits
from available security analysis, implementation, and deployment
experience. Moreover, a standardized solution for federated
authentication and authorization will help to stimulate the deployment
of constrained devices that provide increased security.

Once progress in identifying suitable candidate solutions has been made,
the working group will verify whether the same mechanisms are also
applicable beyond the use of CoAP and DTLS, which are the two main
protocols the group will focus on for access to resources. In
particular, the ability to use the developed solution over HTTP and TLS
will be investigated. Note that the initial focus is on CoAP and HTTP
with DTLS and TLS. Other security protocols may be considered as long as
the primary focus is maintained. The group is scoped to work only on the
web protocols and data carried within them. Furthermore, to guarantee
smooth transition, the integration with existing deployments will be
studied, particularly concerning the use of protocol translation

This work does not make the assumption that the party offering
application layer services is always the same party offering network
access services. ACE will need to interact with CORE and LWIG to
ensure coordination.

The working group has the following tasks:

1) Produce use cases and requirements

2) Identify authentication and authorization mechanisms suitable for
resource access in constrained environments.


Date Milestone
1 Dec 2021 Submission to the IESG of "Admin Interface for the OSCORE Group Manager"
1 Sep 2021 Submission to the IESG of "Key Management for OSCORE Groups in ACE"
1 Aug 2021 Submission to the IESG of "EAP-based Authentication Service for CoAP"
1 Jul 2021 Submission to the IESG of "Protecting EST Payloads with OSCORE"
1 Jul 2021 Submission to the IESG of "Key Provisioning for Group Communication using ACE"
1 Jul 2021 Submission to the IESG of "An Authorization Information Format (AIF) for ACE"
1 Jul 2021 Submission to the IESG of Pub-Sub Profile for Authentication and Authorization for Constrained Environments (ACE)
1 Jun 2021 Submission to IESG of "CoAP Transport for CMPV2" (if adopted)
1 Feb 2021 Call for adoption of "Protecting EST Payloads with OSCORE"
1 Feb 2021 Submission to the IESG of "OSCORE Profile of the Authentication and Authorization for Constrained Environments Framework"
1 Feb 2021 Adoption call of "EAP-based Authentication Service for CoAP"
1 Jan 2021 Adoption call for "CoAP Transport for CMPV2"
1 Sep 2020 WGLC for Group Communications
1 Nov 2018 Submit DTLS Profile for ACE to the IESG for publication as a proposed standard

Done milestones

Date Milestone
Done Submit ACE profile for OSCORE to the IESG for publication as a Proposed Standard
Done Submit "Authentication and Authorization Solution" specification to the IESG for publication as a Proposed Standard.
Done WGLC on OSCORE Profile for ACE
Done WGLC for DTLS Profile for ACE
Done WGLC for OAuth Authentication and Authorization Solution draft
Done Submit CWT Proof of Possession to IESG for publication as proposed standard
Done WGLC on CWT Proof of possession
Done Submit CBOR Web Token draft to the IESG for publication
Done Submit "Authentication and Authorization for ACE" specification as a WG item.
Done Optionally, submit "Use cases and Requirements" document to the IESG for publication as an Informational RFC.
Done Submit "An Architecture for Authorization in Constrained Environments" as a WG item.
Done Submit "Use cases and Requirements" as a WG item.