MQTT-TLS profile of ACE
draft-ietf-ace-mqtt-tls-profile-02
ACE Working Group C. Sengul
Internet-Draft Nominet
Intended status: Standards Track A. Kirby
Expires: May 5, 2020 Oxbotica
P. Fremantle
University of Portsmouth
November 2, 2019
MQTT-TLS profile of ACE
draft-ietf-ace-mqtt-tls-profile-02
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 May 5, 2020.
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Internet-Draft MQTT-TLS profile of ACE November 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 . . . . . . . . . . . . . . . . 4
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) . . . . . . . 8
2.2.1. Client-Server Authentication over TLS and MQTT . . . 8
2.2.2. authz-info: The Authorization Information Topic . . . 9
2.2.3. Transporting Access Token Inside the MQTT CONNECT . . 9
2.2.4. Authentication Using AUTH Property . . . . . . . . . 11
2.2.4.1. Proof-of-Possession Using a Challenge from the
TLS session . . . . . . . . . . . . . . . . . . . 11
2.2.4.2. Proof-of-Possession via Broker-generated
Challenge/Response . . . . . . . . . . . . . . . 12
2.2.4.3. Unauthorised Request: Authorisation Server
Discovery . . . . . . . . . . . . . . . . . . . . 12
2.2.5. Token Validation . . . . . . . . . . . . . . . . . . 13
2.2.6. The Broker's Response to Client Connection Request . 13
3. Authorizing PUBLISH Messages . . . . . . . . . . . . . . . . 14
3.1. PUBLISH Messages from the Publisher Client to the Broker 14
3.2. PUBLISH Messages from the Broker to the Subscriber
Clients . . . . . . . . . . . . . . . . . . . . . . . . . 14
4. Authorizing SUBSCRIBE Messages . . . . . . . . . . . . . . . 15
5. Token Expiration and Reauthentication . . . . . . . . . . . . 15
6. Handling Disconnections and Retained Messages . . . . . . . . 16
7. Reduced Protocol Interactions for MQTT v3.1.1 . . . . . . . . 16
7.1. Token Transport . . . . . . . . . . . . . . . . . . . . . 16
7.2. Handling Authorization Errors . . . . . . . . . . . . . . 18
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
9. Security Considerations . . . . . . . . . . . . . . . . . . . 19
10. Privacy Considerations . . . . . . . . . . . . . . . . . . . 20
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
11.1. Normative References . . . . . . . . . . . . . . . . . . 20
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