AEAD Key Usage Limits in OSCORE
draft-hoeglund-core-oscore-key-limits-00
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Active Internet-Draft (individual)
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Rikard Höglund
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Marco Tiloca
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2021-02-19
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Consensus Boilerplate |
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Unknown
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On Agenda |
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core at IETF-110
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I-D Exists
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CoRE Working Group R. Hoeglund
Internet-Draft M. Tiloca
Updates: 8613 (if approved) RISE AB
Intended status: Standards Track February 19, 2021
Expires: August 23, 2021
AEAD Key Usage Limits in OSCORE
draft-hoeglund-core-oscore-key-limits-00
Abstract
Object Security for Constrained RESTful Environments (OSCORE) uses
AEAD algorithms to ensure confidentiality and integrity of exchanged
messages. Due to known issues allowing forgery attacks against AEAD
algorithms, limits should be followed on the number of times a
specific key is used for encryption or decryption. This document
defines how two peers using OSCORE must take these limits into
account and what steps they must take to preserve the security of
their communications. Therefore, this document updates RFC8613.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 23, 2021.
Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
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Hoeglund & Tiloca Expires August 23, 2021 [Page 1]
Internet-Draft AEAD Key Usage Limits in OSCORE February 2021
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Problem Overview . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Limits for 'q' and 'v' . . . . . . . . . . . . . . . . . 4
3. Additional Information in the Security Context . . . . . . . 4
4. OSCORE Messages Processing . . . . . . . . . . . . . . . . . 5
4.1. Protecting a Request or a Response . . . . . . . . . . . 5
4.2. Verifying a Request or a Response . . . . . . . . . . . . 6
5. Methods for Rekeying OSCORE . . . . . . . . . . . . . . . . . 6
6. Security Considerations . . . . . . . . . . . . . . . . . . . 7
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 7
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . 7
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8
9.1. Normative References . . . . . . . . . . . . . . . . . . 8
9.2. Informative References . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9
1. Introduction
Object Security for Constrained RESTful Environments (OSCORE)
[RFC8613] provides end-to-end protection of CoAP [RFC7252] messages
at the application-layer, ensuring message confidentiality and
integrity, replay protection, as well as binding of response to
request between a sender and a recipient.
In particular, OSCORE uses AEAD algorithms to provide confidentiality
and integrity of messages exchanged between two peers. Due to known
issues allowing forgery attacks against AEAD algorithms, limits
should be followed on the number of times a specific key is used to
perform encryption or decryption [I-D.irtf-cfrg-aead-limits].
Should these limits be exceeded, an adversary may break the security
properties of the AEAD algorithm, such as message confidentiality and
integrity, e.g. by performing a message forgery attack. The original
OSCORE specification [RFC8613] does not consider such limits.
This document updates [RFC8613] and defines when a peer must stop
using an OSCORE Security Context shared with another peer, due to the
reached key usage limits. When this happens, the two peers have to
establish a new Security Context with new keying material, in order
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