MQTT-TLS profile of ACE
draft-ietf-ace-mqtt-tls-profile-03
ACE Working Group C. Sengul
Internet-Draft Nominet
Intended status: Standards Track A. Kirby
Expires: June 22, 2020 Oxbotica
P. Fremantle
University of Portsmouth
December 20, 2019
MQTT-TLS profile of ACE
draft-ietf-ace-mqtt-tls-profile-03
Abstract
This document specifies a profile for the ACE (Authentication and
Authorization for Constrained Environments) framework to enable
authorization in an MQTT-based publish-subscribe messaging system.
Proof-of-possession keys, bound to OAuth2.0 access tokens, are used
to authenticate and authorize MQTT Clients. The protocol relies on
TLS for confidentiality and server authentication.
Status of This Memo
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This Internet-Draft will expire on June 22, 2020.
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Internet-Draft MQTT-TLS profile of ACE December 2019
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 4
1.2. ACE-Related Terminology . . . . . . . . . . . . . . . . . 4
1.3. MQTT-Related Terminology . . . . . . . . . . . . . . . . 5
2. Authorizing Connection Requests . . . . . . . . . . . . . . . 7
2.1. Client Token Request to the Authorization Server (AS) . . 8
2.2. Client Connection Request to the Broker (C) . . . . . . . 9
2.2.1. Client-Server Authentication over TLS and MQTT . . . 9
2.2.2. authz-info: The Authorization Information Topic . . . 10
2.2.3. Transporting Access Token Inside the MQTT CONNECT . . 11
2.2.4. Authentication Using AUTH Property . . . . . . . . . 12
2.2.4.1. Proof-of-Possession Using a Challenge from the
TLS session . . . . . . . . . . . . . . . . . . . 13
2.2.4.2. Proof-of-Possession via Broker-generated
Challenge/Response . . . . . . . . . . . . . . . 13
2.2.4.3. Unauthorised Request: Authorisation Server
Discovery . . . . . . . . . . . . . . . . . . . . 14
2.2.5. Token Validation . . . . . . . . . . . . . . . . . . 14
2.2.6. The Broker's Response to Client Connection Request . 15
3. Authorizing PUBLISH and SUBSCRIBE Messages . . . . . . . . . 15
3.1. PUBLISH Messages from the Publisher Client to the Broker 16
3.2. PUBLISH Messages from the Broker to the Subscriber
Clients . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.3. Authorizing SUBSCRIBE Messages . . . . . . . . . . . . . 16
4. Token Expiration and Reauthentication . . . . . . . . . . . . 17
5. Handling Disconnections and Retained Messages . . . . . . . . 17
6. Reduced Protocol Interactions for MQTT v3.1.1 . . . . . . . . 18
6.1. Token Transport . . . . . . . . . . . . . . . . . . . . . 18
6.2. Handling Authorization Errors . . . . . . . . . . . . . . 20
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 20
8. Security Considerations . . . . . . . . . . . . . . . . . . . 21
9. Privacy Considerations . . . . . . . . . . . . . . . . . . . 22
10. References . . . . . . . . . . . . . . . . . . . . . . . . . 22
10.1. Normative References . . . . . . . . . . . . . . . . . . 22
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