Internet DRAFT - draft-ietf-suit-mti
draft-ietf-suit-mti
SUIT B. Moran
Internet-Draft Arm Limited
Intended status: Standards Track Ø. Rønningstad
Expires: 15 August 2024 Nordic Semiconductor
A. Tsukamoto
ALAXALA Networks Corp.
12 February 2024
Mandatory-to-Implement Algorithms for Authors and Recipients of Software
Update for the Internet of Things manifests
draft-ietf-suit-mti-05
Abstract
This document specifies algorithm profiles for SUIT manifest parsers
and authors to ensure better interoperability. These profiles apply
specifically to a constrained node software update use case.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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Task Force (IETF). Note that other groups may also distribute
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 15 August 2024.
Copyright Notice
Copyright (c) 2024 IETF Trust and the persons identified as the
document authors. All rights reserved.
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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 carefully, as they describe your rights
and restrictions with respect to this document. Code Components
extracted from this document must include Revised BSD License text as
described in Section 4.e of the Trust Legal Provisions and are
provided without warranty as described in the Revised BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Profiles . . . . . . . . . . . . . . . . . . . . . . . . . . 3
3.1. Symmetric MTI profile:
suit-sha256-hmac-a128kw-a128ctr . . . . . . . . . . . . . 4
3.2. Current Constrained Asymmetric MTI Profile 1:
suit-sha256-es256-ecdh-a128ctr . . . . . . . . . . . . . 4
3.3. Current Constrained Asymmetric MTI Profile 2:
suit-sha256-eddsa-ecdh-a128ctr . . . . . . . . . . . . . 4
3.4. Current AEAD Asymmetric MTI Profile 1:
suit-sha256-es256-ecdh-a128gcm . . . . . . . . . . . . . 5
3.5. Current AEAD Asymmetric MTI Profile 2:
suit-sha256-eddsa-ecdh-chacha-poly . . . . . . . . . . . 5
3.6. Future Constrained Asymmetric MTI Profile 1:
suit-sha256-hsslms-a256kw-a256ctr . . . . . . . . . . . . 5
4. Reporting Profiles . . . . . . . . . . . . . . . . . . . . . 6
5. Security Considerations . . . . . . . . . . . . . . . . . . . 6
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6
7. References . . . . . . . . . . . . . . . . . . . . . . . . . 7
7.1. Normative References . . . . . . . . . . . . . . . . . . 7
7.2. Informative References . . . . . . . . . . . . . . . . . 8
Appendix A. A. Full CDDL . . . . . . . . . . . . . . . . . . . 8
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 11
1. Introduction
Mandatory algorithms may change over time due to an evolving threat
landscape. Algorithms are grouped into algorithm profiles to account
for this. Profiles may be deprecated over time. SUIT will define
five choices of MTI profile specifically for constrained node
software update. These profiles are:
* One Symmetric MTI profile
* Two "Current" Constrained Asymmetric MTI profiles
* Two "Current" AEAD Asymmetric MTI profiles
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* One "Future" Constrained Asymmetric MTI profile
At least one MTI algorithm in each category MUST be FIPS qualified.
Because SUIT presents an asymmetric communication profile, with
powerful/complex manifest authors and constrained manifest
recipients, the requirements for Recipients and Authors are
different.
Recipients MAY choose which MTI profile they wish to implement. It
is RECOMMENDED that they implement the "Future" Asymmetric MTI
profile. Recipients MAY implement any number of other profiles.
Authors MUST implement all MTI profiles. Authors MAY implement any
number of other profiles.
AEAD is preferred over un-authenticated encryption. Where possible
an AEAD profile SHOULD be selected. Certain constrained IoT
applications require streaming decryption, which necessitates a non-
AEAD ecryption algorithm. If the application is not a constrained
device, the two AEAD profiles are RECOMMENDED.
Other use-cases of SUIT MAY define their own MTI algorithms.
2. Algorithms
The algorithms that form a part of the profiles defined in this
document are grouped into:
* Digest Algorithms
* Authentication Algorithms
* Key Exchange Algorithms
* Encryption Algorithms
3. Profiles
Recognized profiles are defined below.
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3.1. Symmetric MTI profile: suit-sha256-hmac-a128kw-a128ctr
+================+=================+==========+
| Algorithm Type | Algorithm | COSE Key |
+================+=================+==========+
| Digest | SHA-256 | -16 |
+----------------+-----------------+----------+
| Authentication | HMAC-256 | 5 |
+----------------+-----------------+----------+
| Key Exchange | A128KW Key Wrap | -3 |
+----------------+-----------------+----------+
| Encryption | A128CTR | -65534 |
+----------------+-----------------+----------+
Table 1
3.2. Current Constrained Asymmetric MTI Profile 1: suit-sha256-es256-
ecdh-a128ctr
+================+==================+==========+
| Algorithm Type | Algorithm | COSE Key |
+================+==================+==========+
| Digest | SHA-256 | -16 |
+----------------+------------------+----------+
| Authentication | ES256 | -7 |
+----------------+------------------+----------+
| Key Exchange | ECDH-ES + A128KW | -29 |
+----------------+------------------+----------+
| Encryption | A128CTR | -65534 |
+----------------+------------------+----------+
Table 2
3.3. Current Constrained Asymmetric MTI Profile 2: suit-sha256-eddsa-
ecdh-a128ctr
+================+==================+==========+
| Algorithm Type | Algorithm | COSE Key |
+================+==================+==========+
| Digest | SHA-256 | -16 |
+----------------+------------------+----------+
| Authentication | EDDSA | -8 |
+----------------+------------------+----------+
| Key Exchange | ECDH-ES + A128KW | -29 |
+----------------+------------------+----------+
| Encryption | A128CTR | -65534 |
+----------------+------------------+----------+
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Table 3
3.4. Current AEAD Asymmetric MTI Profile 1: suit-sha256-es256-ecdh-
a128gcm
+================+==================+==========+
| Algorithm Type | Algorithm | COSE Key |
+================+==================+==========+
| Digest | SHA-256 | -16 |
+----------------+------------------+----------+
| Authentication | ES256 | -7 |
+----------------+------------------+----------+
| Key Exchange | ECDH-ES + A128KW | -29 |
+----------------+------------------+----------+
| Encryption | A128GCM | 1 |
+----------------+------------------+----------+
Table 4
3.5. Current AEAD Asymmetric MTI Profile 2: suit-sha256-eddsa-ecdh-
chacha-poly
+================+===================+==========+
| Algorithm Type | Algorithm | COSE Key |
+================+===================+==========+
| Digest | SHA-256 | -16 |
+----------------+-------------------+----------+
| Authentication | EDDSA | -8 |
+----------------+-------------------+----------+
| Key Exchange | ECDH-ES + A128KW | -29 |
+----------------+-------------------+----------+
| Encryption | ChaCha20/Poly1305 | 24 |
+----------------+-------------------+----------+
Table 5
3.6. Future Constrained Asymmetric MTI Profile 1: suit-sha256-hsslms-
a256kw-a256ctr
+================+===========+==========+
| Algorithm Type | Algorithm | COSE Key |
+================+===========+==========+
| Digest | SHA-256 | -16 |
+----------------+-----------+----------+
| Authentication | HSS-LMS | -46 |
+----------------+-----------+----------+
| Key Exchange | A256KW | -5 |
+----------------+-----------+----------+
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| Encryption | A256CTR | -65532 |
+----------------+-----------+----------+
Table 6
4. Reporting Profiles
When using reverse-direction communication, particularly data
structures that are designed for reporting of update capabilities,
status, progress, or success, the same profile as the is used on the
SUIT manifest SHOULD be used. There are cases where this is not
possible, such as suit-sha256-hsslms-a256kw-a256ctr. In this case,
the closest equivalent profile SHOULD be used, for example suit-
sha256-es256-ecdh-a128ctr.
5. Security Considerations
For the avoidance of doubt, there are scenarios where payload or
manifest encryption are not required. In these scenarios, the
encryption element of the selected profile is simply not used.
AES-CTR mode is specified, see [RFC9459]. All of the AES-CTR
security considerations in [RFC9459] apply. A non-AEAD encryption
mode is specified in this draft due to the following mitigating
circumstances:
* Streaming decryption must be supported. Therefore, there is no
difference between AEAD and plaintext hash verification.
* Out-of-order decryption must be supported. Therefore, we must use
a stream cipher that supports random access.
* There are no chosen plaintext attacks: the plaintext is
authenticated prior to encryption.
* Content Encryption Keys MUST be used to encrypt only once. See
[I-D.ietf-suit-firmware-encryption].
As a result of these mitigating circumstances, AES-CTR is the most
appropriate cipher for typical software/firmware delivery scenarios.
6. IANA Considerations
IANA is requested to create a page for COSE Algorithm Profiles within
the category for Software Update for the Internet of Things (SUIT)
IANA is also requested to create a registry for COSE Alforithm
Profiles within this page. The initial content of the registry is:
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+=============+=========+======+====+========+==========+==========+=========+
|Profile |Status |Digest|Auth|Key |Encryption|Descriptor|Reference|
| | | | |Exchange| |Array | |
+=============+=========+======+====+========+==========+==========+=========+
|suit-sha256- |MANDATORY|-16 |5 |-3 |-65534 |[-16, 5, |Section |
|hmac-a128kw- | | | | | |-3, |3.1 |
|a128ctr | | | | | |-65534] | |
+-------------+---------+------+----+--------+----------+----------+---------+
|suit- |MANDATORY|-16 |-7 |-29 |-65534 |[-16, -7, |Section |
|sha256-es256-| | | | | |-29, |3.2 |
|ecdh-a128ctr | | | | | |-65534] | |
+-------------+---------+------+----+--------+----------+----------+---------+
|suit-sha256- |MANDATORY|-16 |-8 |-29 |-65534 |[-16, -8, |Section |
|eddsa-ecdh- | | | | | |-29, |3.3 |
|a128ctr | | | | | |-65534] | |
+-------------+---------+------+----+--------+----------+----------+---------+
|suit- |MANDATORY|-16 |-7 |-29 |1 |[-16, -7, |Section |
|sha256-es256-| | | | | |-29, 1] |3.4 |
|ecdh-a128gcm | | | | | | | |
+-------------+---------+------+----+--------+----------+----------+---------+
|suit-sha256- |MANDATORY|-16 |-8 |-29 |24 |[-16, -8, |Section |
|eddsa-ecdh- | | | | | |-29, 24] |3.5 |
|chacha-poly | | | | | | | |
+-------------+---------+------+----+--------+----------+----------+---------+
|suit-sha256- |MANDATORY|-16 |-46 |-5 |-65532 |[-16, -46,|Section |
|hsslms- | | | | | |-5, |3.6 |
|a256kw- | | | | | |-65532] | |
|a256ctr | | | | | | | |
+-------------+---------+------+----+--------+----------+----------+---------+
Table 7
New entries to this registry require standards action.
7. References
7.1. Normative References
[I-D.ietf-suit-manifest]
Moran, B., Tschofenig, H., Birkholz, H., Zandberg, K., and
O. Rønningstad, "A Concise Binary Object Representation
(CBOR)-based Serialization Format for the Software Updates
for Internet of Things (SUIT) Manifest", Work in Progress,
Internet-Draft, draft-ietf-suit-manifest-25, 5 February
2024, <https://datatracker.ietf.org/doc/html/draft-ietf-
suit-manifest-25>.
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[RFC8152] Schaad, J., "CBOR Object Signing and Encryption (COSE)",
RFC 8152, DOI 10.17487/RFC8152, July 2017,
<https://www.rfc-editor.org/rfc/rfc8152>.
[RFC8778] Housley, R., "Use of the HSS/LMS Hash-Based Signature
Algorithm with CBOR Object Signing and Encryption (COSE)",
RFC 8778, DOI 10.17487/RFC8778, April 2020,
<https://www.rfc-editor.org/rfc/rfc8778>.
[RFC9052] Schaad, J., "CBOR Object Signing and Encryption (COSE):
Structures and Process", STD 96, RFC 9052,
DOI 10.17487/RFC9052, August 2022,
<https://www.rfc-editor.org/rfc/rfc9052>.
[RFC9459] Housley, R. and H. Tschofenig, "CBOR Object Signing and
Encryption (COSE): AES-CTR and AES-CBC", RFC 9459,
DOI 10.17487/RFC9459, September 2023,
<https://www.rfc-editor.org/rfc/rfc9459>.
7.2. Informative References
[I-D.ietf-suit-firmware-encryption]
Tschofenig, H., Housley, R., Moran, B., Brown, D., and K.
Takayama, "Encrypted Payloads in SUIT Manifests", Work in
Progress, Internet-Draft, draft-ietf-suit-firmware-
encryption-18, 23 October 2023,
<https://datatracker.ietf.org/doc/html/draft-ietf-suit-
firmware-encryption-18>.
[IANA-COSE]
"CBOR Object Signing and Encryption (COSE)", 2022,
<https://www.iana.org/assignments/cose/cose.xhtml>.
Appendix A. A. Full CDDL
The following CDDL creates a subset of COSE for use with SUIT. Both
tagged and untagged messages are defined. SUIT only uses tagged COSE
messages, but untagged messages are also defined for use in protocols
that share a ciphersuite with SUIT.
To be valid, the following CDDL MUST have the COSE CDDL appended to
it. The COSE CDDL can be obtained by following the directions in
[RFC9052], Section 1.4.
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SUIT_COSE_tool_tweak /= suit-sha256-hmac-a128kw-a128ctr
SUIT_COSE_tool_tweak /= suit-sha256-es256-ecdh-a128ctr
SUIT_COSE_tool_tweak /= suit-sha256-eddsa-ecdh-a128ctr
SUIT_COSE_tool_tweak /= suit-sha256-eddsa-ecdh-chacha-poly
SUIT_COSE_tool_tweak /= suit-sha256-hsslms-a256kw-a256ctr
SUIT_COSE_tool_tweak /= SUIT_COSE_Profiles
SUIT_COSE_Profiles /= SUIT_COSE_Profile_HMAC_A128KW_A128CTR
SUIT_COSE_Profiles /= SUIT_COSE_Profile_ES256_ECDH_A128CTR
SUIT_COSE_Profiles /= SUIT_COSE_Profile_EDDSA_ECDH_A128CTR
SUIT_COSE_Profiles /= SUIT_COSE_Profile_ES256_ECDH_A128GCM
SUIT_COSE_Profiles /= SUIT_COSE_Profile_EDDSA_ECDH_CHACHA20_POLY1304
SUIT_COSE_Profiles /= SUIT_COSE_Profile_HSSLMS_A256KW_A256CTR
suit-sha256-hmac-a128kw-a128ctr = [-16, 5, -3, -65534]
suit-sha256-es256-ecdh-a128ctr = [-16, -7, -25, -65534]
suit-sha256-eddsa-ecdh-a128ctr = [-16, -8, -25, -65534]
suit-sha256-es256-ecdh-a128gcm = [-16, -7, -25, 1]
suit-sha256-eddsa-ecdh-chacha-poly = [-16, -8, -25, 24]
suit-sha256-hsslms-a256kw-a256ctr = [-16, -46, -5, -65532]
SUIT_COSE_Profile_HMAC_A128KW_A128CTR = SUIT_COSE_Profile<5, -65534> .and COSE_Messages
SUIT_COSE_Profile_ES256_ECDH_A128CTR = SUIT_COSE_Profile<-7,-65534> .and COSE_Messages
SUIT_COSE_Profile_EDDSA_ECDH_A128CTR = SUIT_COSE_Profile<-8,-65534> .and COSE_Messages
SUIT_COSE_Profile_ES256_ECDH_A128GCM = SUIT_COSE_Profile<-7,1> .and COSE_Messages
SUIT_COSE_Profile_EDDSA_ECDH_CHACHA20_POLY1304 = SUIT_COSE_Profile<-8,24> .and COSE_Messages
SUIT_COSE_Profile_HSSLMS_A256KW_A256CTR = SUIT_COSE_Profile<-46,-65532> .and COSE_Messages
SUIT_COSE_Profile<authid, encid> = SUIT_COSE_Messages<authid,encid>
SUIT_COSE_Messages<authid, encid> = SUIT_COSE_Untagged_Message<authid, encid> /
SUIT_COSE_Tagged_Message<authid, encid>
SUIT_COSE_Untagged_Message<authid, encid> = SUIT_COSE_Sign<authid> /
SUIT_COSE_Sign1<authid> / SUIT_COSE_Encrypt<encid> /
SUIT_COSE_Encrypt0<encid> / SUIT_COSE_Mac<authid> /
SUIT_COSE_Mac0<authid>
SUIT_COSE_Tagged_Message<authid, encid> = SUIT_COSE_Sign_Tagged<authid> /
SUIT_COSE_Sign1_Tagged<authid> / SUIT_COSE_Encrypt_Tagged<encid> /
SUIT_COSE_Encrypt0_Tagged<encid> / SUIT_COSE_Mac_Tagged<authid> /
SUIT_COSE_Mac0_Tagged<authid>
; Note: This is not the same definition as is used in COSE.
; It restricts a COSE header definition further without
; repeating the COSE definition. It should be merged
; with COSE by using the CDDL .and operator.
SUIT_COSE_Profile_Headers<algid> = (
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protected : bstr .cbor SUIT_COSE_alg_map<algid>,
unprotected : SUIT_COSE_header_map
)
SUIT_COSE_alg_map<algid> = {
1 => algid,
* int => any
}
SUIT_COSE_header_map = {
* int => any
}
SUIT_COSE_Sign_Tagged<authid> = #6.98(SUIT_COSE_Sign<authid>)
SUIT_COSE_Sign<authid> = [
SUIT_COSE_Profile_Headers<authid>,
payload : bstr / nil,
signatures : [+ SUIT_COSE_Signature<authid>]
]
SUIT_COSE_Signature<authid> = [
SUIT_COSE_Profile_Headers<authid>,
signature : bstr
]
SUIT_COSE_Sign1_Tagged<authid> = #6.18(SUIT_COSE_Sign1<authid>)
SUIT_COSE_Sign1<authid> = [
SUIT_COSE_Profile_Headers<authid>,
payload : bstr / nil,
signature : bstr
]
SUIT_COSE_Encrypt_Tagged<encid> = #6.96(SUIT_COSE_Encrypt<encid>)
SUIT_COSE_Encrypt<encid> = [
SUIT_COSE_Profile_Headers<encid>,
ciphertext : bstr / nil,
recipients : [+SUIT_COSE_recipient<encid>]
]
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SUIT_COSE_recipient<encid> = [
SUIT_COSE_Profile_Headers<encid>,
ciphertext : bstr / nil,
? recipients : [+SUIT_COSE_recipient<encid>]
]
SUIT_COSE_Encrypt0_Tagged<encid> = #6.16(SUIT_COSE_Encrypt0<encid>)
SUIT_COSE_Encrypt0<encid> = [
SUIT_COSE_Profile_Headers<encid>,
ciphertext : bstr / nil,
]
SUIT_COSE_Mac_Tagged<authid> = #6.97(SUIT_COSE_Mac<authid>)
SUIT_COSE_Mac<authid> = [
SUIT_COSE_Profile_Headers<authid>,
payload : bstr / nil,
tag : bstr,
recipients :[+SUIT_COSE_recipient<authid>]
]
SUIT_COSE_Mac0_Tagged<authid> = #6.17(SUIT_COSE_Mac0<authid>)
SUIT_COSE_Mac0<authid> = [
SUIT_COSE_Profile_Headers<authid>,
payload : bstr / nil,
tag : bstr,
]
Authors' Addresses
Brendan Moran
Arm Limited
Email: brendan.moran.ietf@gmail.com
Øyvind Rønningstad
Nordic Semiconductor
Email: oyvind.ronningstad@gmail.com
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Akira Tsukamoto
ALAXALA Networks Corp.
Email: akira.tsukamoto@alaxala.com
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