Group OSCORE - Secure Group Communication for CoAP
draft-ietf-core-oscore-groupcomm-05
CoRE Working Group M. Tiloca
Internet-Draft RISE AB
Intended status: Standards Track G. Selander
Expires: January 6, 2020 F. Palombini
Ericsson AB
J. Park
Universitaet Duisburg-Essen
July 05, 2019
Group OSCORE - Secure Group Communication for CoAP
draft-ietf-core-oscore-groupcomm-05
Abstract
This document describes a mode for protecting group communication
over the Constrained Application Protocol (CoAP). The proposed mode
relies on Object Security for Constrained RESTful Environments
(OSCORE) and the CBOR Object Signing and Encryption (COSE) format.
In particular, it defines how OSCORE is used in a group communication
setting, while fulfilling the same security requirements for group
requests and responses. Source authentication of all messages
exchanged within the group is provided by means of digital signatures
produced by the sender and embedded in the protected CoAP messages.
Status of This Memo
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Copyright Notice
Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved.
Tiloca, et al. Expires January 6, 2020 [Page 1]
Internet-Draft Group OSCORE July 2019
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. OSCORE Security Context . . . . . . . . . . . . . . . . . . . 5
2.1. Management of Group Keying Material . . . . . . . . . . . 8
2.2. Wrap-Around of Partial IVs . . . . . . . . . . . . . . . 9
3. The COSE Object . . . . . . . . . . . . . . . . . . . . . . . 10
3.1. Updated external_aad . . . . . . . . . . . . . . . . . . 10
3.1.1. Updated external_aad for Encryption . . . . . . . . . 10
3.1.2. Updated external_aad for Signing . . . . . . . . . . 11
3.2. Use of the 'kid' Parameter . . . . . . . . . . . . . . . 12
3.3. Updated 'unprotected' Field . . . . . . . . . . . . . . . 12
4. OSCORE Header Compression . . . . . . . . . . . . . . . . . . 12
4.1. Encoding of the OSCORE Option Value . . . . . . . . . . . 12
4.2. Encoding of the OSCORE Payload . . . . . . . . . . . . . 13
4.3. Examples of Compressed COSE Objects . . . . . . . . . . . 14
5. Message Binding, Sequence Numbers, Freshness and Replay
Protection . . . . . . . . . . . . . . . . . . . . . . . . . 15
5.1. Synchronization of Sender Sequence Numbers . . . . . . . 15
6. Message Processing . . . . . . . . . . . . . . . . . . . . . 16
6.1. Protecting the Request . . . . . . . . . . . . . . . . . 16
6.2. Verifying the Request . . . . . . . . . . . . . . . . . . 17
6.3. Protecting the Response . . . . . . . . . . . . . . . . . 17
6.4. Verifying the Response . . . . . . . . . . . . . . . . . 18
7. Responsibilities of the Group Manager . . . . . . . . . . . . 18
8. Security Considerations . . . . . . . . . . . . . . . . . . . 19
8.1. Group-level Security . . . . . . . . . . . . . . . . . . 20
8.2. Uniqueness of (key, nonce) . . . . . . . . . . . . . . . 21
8.3. Management of Group Keying Material . . . . . . . . . . . 21
8.4. Update of Security Context and Key Rotation . . . . . . . 22
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