]> Arm Limited

brendan.moran.ietf@gmail.com

Fraunhofer SIT

Rheinstrasse 75 Darmstadt 64295 Germany henk.birkholz@ietf.contact

Security SUIT Internet-Draft The Software Update for the Internet of Things (SUIT) manifest provides a way for many different update and boot workflows to be described by a common format. This specification describes a lightweight feedback mechanism that allows a developer in possession of a manifest to reconstruct the decisions made and actions performed by a manifest processor.

Introduction This specification describes a SUIT-specific logging container that creates a lightweight feedback mechanism for developers in the event that an update or boot fails in the manifest processor. A SUIT manifest processor can fail to install or boot an update for many reasons. Frequently, the error codes generated by such systems fail to provide developers with enough information to find root causes and produce corrective actions, resulting in extra effort to reproduce failures. Logging the results of each SUIT command can simplify this process. While it is possible to report the results of SUIT commands through existing logging or attestation mechanisms, this comes with several drawbacks: data inflation, particularly when designed for text-based logging missing information elements missing support for multiple components The CBOR objects defined in this document allow devices to: report a trace of how an update was performed report expected vs. actual values for critical checks describe the installation of complex multi-component architectures describe the measured properties of a system report the exact reason for a parsing failure

Conventions and Terminology The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in BCP 14 when, and only when, they appear in all capitals, as shown here. Terms used in this specification include: Boot: initialization of an executable image. Although this specification refers to boot, any boot-specific operations described are equally applicable to starting an executable in an OS context.

The SUIT_Record If the developer has a copy of the manifest, then they need little information to reconstruct what the manifest processor has done. They simply need any data that influences the control flow of the manifest. The manifest only supports the following control flow primitives: Set Component Set/Override Parameters Try-Each Run Sequence Conditions Of these, only conditions change the behavior of the processor from the default, and then only when the condition fails. To reconstruct the flow of a manifest, a developer needs a list of metadata about failed conditions: the current manifest the current section the offset into the current section the current component index the "reason" for failure Most conditions compare a parameter to an actual value, so the "reason" is typically the actual value. Since it is possible that a non-condition command (directive) may fail in an exceptional circumstance, a failure code for a non condition command must be included as well. However, a failed directive will terminate processing of the manifest. To accommodate for a failed command and for explicit "completion," an additional "result" element is included as well, however this is included in the SUIT_Report, see . In the case of a command failure, the failure reason is typically a numeric error code. However, these error codes need to be standardised in order to be useful. This approach effectively compacts the log of operations taken using the SUIT Manifest as a dictionary. This enables a full reconstruction of the log using a matching decompaction tool.

suit-record-manifest-id is used to identify which manifest contains the command that caused the record to be generated. The manifest id is a list of integers that form a walk of the manifest tree, starting at the root. An empty list indicates that the command was contained in the root manifest. If the list is not empty, the command was contained in one of the root manifest's dependencies, or nested even further below that. For example, suppose that the root manifest has 3 dependencies and each of those dependencies has 2 dependencies of its own: Root Dependency A (index 0) Dependency AA (index 0,0) Dependency AB (index 0,1) Dependency B (index 1) Dependency BA (index 1,0) Dependency BB (index 1,1) Dependency C (index 2) Dependency CA (index 2,0) Dependency CB (index 2,1) A manifest-id of [1,0] would indicate that the current command was contained within Dependency BA. Similarly, a manifest-id of [2,1] would indicate Dependency CB suit-record-manifest-section indicates which section of the manifest was active. This is used in addition to an offset so that the developer can index into severable sections in a predictable way. The value of this element is the value of the key that identified the section in the manifest. suit-record-section-offset is the number of bytes into the current section at which the current command is located. suit-record-component-index is the index of the component that was specified at the time that the report was generated. This field is necessary due to the availability of set-current-component values of True and a list of components. Both of these values cause the manifest processor to loop over commands using a series of component-ids, so the developer needs to know which was selected when the command executed. suit-record-properties contains any measured properties that led to the command failure. For example, this could be the actual value of a SUIT_Digest or class identifier. This is encoded in a SUIT_Parameters block as defined in .

The SUIT_Report Some metadata is common to all records, such as the root manifest: the manifest that is the entry-point for the manifest processor. This metadata is aggregated with a list of SUIT_Records. The SUIT_Report may also contain a list of any system properties that were measured and reported, and a reason for a failure if one occurred.

SUIT_Reference, ? suit-report-nonce => bstr, suit-report-records => \ \[ * SUIT_Record / system-property-claims \], suit-report-result => true / { suit-report-result-code => int, suit-report-result-record => SUIT_Record, suit-report-result-reason => SUIT_Report_Reasons, }, ? suit-report-capability-report => SUIT_Capability_Report, $$SUIT_Report_Extensions } system-property-claims = { system-component-id => SUIT_Component_Identifier, + SUIT_Parameters, } ]]>

The suit-reference provides a reference URI and digest for a suit manifest. The URI MUST be the canonical URI that is provided in the manifest. The digest is the digest of the manifest. NOTE: The digest is used in preference to other identifiers in the manifest because it allows a manifest to be uniquely identified (collision resistance) whereas other identifiers, such as the sequence number, can collide, particularly in scenarios with multiple trusted signers. The following CDDL describes a SUIT_Reference.

suit-report-manifest-digest provides a SUIT_Digest (as defined in ) that is the characteristic digest of the Root manifest. suit-report-manifest-uri provides the reference URI that was provided in the root manifest. suit-report-nonce provides a container for freshness or replay protection information. This field MAY be omitted where the suit-report is authenticated within a container that provides freshness already. For example, attestation evidence typically contains a proof of freshness.

SUIT_Report_Records suit-report-records is a list of 0 or more SUIT_Records or system-property-claims. Because SUIT_Records are only generated on failure, in simple cases this can be an empty list. SUIT_Records and suit-system-property-claims are merged into a single list because this reduces the overhead for a constrained node that generates this report. The use of a single append-only log allows report generators to use simple memory management. The concept of append-only logs for software supply chains is explained in . Because the system-property-claims are encoded as maps and SUIT_Records are encoded as lists, a recipient need only filter the CBOR Type-5 entries from suit-report-records to obtain all system-property-claims. System Properties can be extracted from suit-report-records by filtering suit-report-records for maps. System Properties are a list of measured or asserted properties of the system that creates the SUIT_Report. These properties are scoped by component identifier. Because this list is expected to be constructed on the fly by a constrained node, component identifiers may appear more than once. A recipient may convert the result to a more conventional structure:

{ + SUIT_Parameters, } } ]]>

SUIT_Report Result suit-report-result provides a mechanism to show that the SUIT procedure completed successfully (value is true) or why it failed (value is a map of an error code and a SUIT_Record). suit-report-result-reason gives a high-level explanation of the failure. These reasons are intended for interoperable implementations. The reasons are divided into a small number of groups: suit-report-reason-cbor-parse: a parsing error was encountered by the CBOR parser. suit-report-reason-cose-unsupported: an unusupported COSE structure or header was encountered. suit-report-reason-alg-unsupported: an unsupported COSE algorithm was encountered. suit-report-reason-unauthorised: Signature/MAC verification failed. suit-report-reason-command-unsupported: an unsupported command was encountered. suit-report-reason-component-unsupported: The manifest declared a component/prefix that does not exist. suit-report-reason-component-unauthorised: The manifest declared a component that is not accessible by the signer. suit-report-reason-parameter-unsupported: The manifest used a parameter that does not exist. suit-report-severing-unsupported: The manifest uses severable fields but the Manifest Processor doesn't support them. suit-report-reason-condition-failed: A condition failed with soft- failure off. suit-report-reason-operation-failed: A command failed (e.g., download/copy/swap/write) The suit-report-result-code reports an internal error code that is provided for debugging reasons. This code is not intended for interoperability. The suit-report-result-record indicates the exact point in the manifest or manifest dependency tree where the error occurred. suit-report-capability-report provides a mechanism to report the capabilities of the Manifest Processor. The SUIT_Capability_Report is described in . The capability report is optional to include in the SUIT_Report, according to an application-specific policy. While the SUIT_Capability_Report is not expected to be very large, applications should ensure that they only report capabilities when necessary in order to conserve bandwidth. A capability report is not necessary except when: A client explicitly requests the capability report, or A manifest attempts to use a capability that the Manifest Processor does not implement.

Attestation Where Remote Attestation (see , the RATS Architecture) is in use, the RATS Verifier (Verifier hereafter) requires a set of Attestation Evidence. Attestation Evidence contains Evidence Claims about the Attester. These Evidence Claims contain measurements about the Attester. Many of these measurements are the same measurements that are generated in SUIT, which means that a SUIT_Report contains most of the Claims and some of the Endorsements that a Verifier requires. Using a SUIT_Manifest and a SUIT_Report, improves a well-informed Verifier's ability to appraise the trustworthiness of a remote device. Remote attestation is done by using the SUIT_Manifest_Envelope along with the SUIT_Report to reconstruct the state of the device at boot time. By embedding data used for remote attestation in the SUIT_Report, a remote device can use a verifiable data structure, such as an append-only log, to notarize both measurements and debug/failure information via the same document. This document can then be conveyed to a Verifier as a part of the Attestation Evidence. A Remote Attestation format to convey Attestation Evidence, such as an Entity Attestation Token (EAT, see ), that contains a SUIT_Report MUST also include an integrity measurement of the Manifest Processor & Report Generator. When a Concise Reference Integrity Manifest (CoRIM, see ) is delivered in a SUIT_Manifest_Envelope, this codifies the delivery of appraisal information to the Verifier: The Firmware Distributor: sends the SUIT_Manifest_Envelope to the Verifier without payload or text, but with CoRIM sends the SUIT_Manifest_Envelope to the recipient without CoRIM, or text, but with payload The Recipient: Installs the firmware as described in the SUIT_Manifest and generates a SUIT_report, which is encapsulated in an EAT by the installer and sent to the Firmware Distributor. Boots the firmware as described in the SUIT_Manifest and creates a SUIT_report, which is encapsulated in an EAT by the installer and sent to the Firmware Distributor. The Firmware Distributor sends both reports to the Verifier (separately or together) The Verifier: Reconstructs the state of the device using the manifest Compares this state to the CoRIM Returns an Attestation Report to the Firmware Distributor This approach simplifies the design of the bootloader since it is able to use an append-only log. It allows a Verifier to validate this report against a signed CoRIM that is provided by the firmware author, which simplifies the delivery chain of verification information to the Verifier. This information is not intended as Attestation Evidence and while an Attestation Report MAY provide this information for conveying error codes and/or failure reports, it SHOULD be translated into general-purpose claims for use by the Relying Party.

Capability Reporting Because SUIT is extensible, a manifest author must know what capabilities a device has available. To enable this, a capability report is a set of lists that define which commands, parameters, algorithms, and component IDs are supported by a manifest processor. The CDDL for a SUIT_Capability_Report follows:

[+ SUIT_Component_Capability ] suit-command-capabilities => [+ int], suit-parameters-capabilities => [+ int], suit-crypt-algo-capabilities => [+ int], ? suit-envelope-capabilities => [+ int], ? suit-manifest-capabilities => [+ int], ? suit-common-capabilities => [+ int], ? suit-text-capabilities => [+ int], ? suit-text-component-capabilities => [+ int], ? suit-dependency-capabilities => [+ int], * [+int] => [+ int], $$SUIT_Capability_Report_Extensions } SUIT_Component_Capability = [*bstr,?true] ]]>

A SUIT_Component_Capability is similar to a SUIT_Component_ID, with one difference: it may optionally be terminated by a CBOR 'true' which acts as a wild-card match for any component with a prefix matching the SUIT_Component_Capability leading up to the 'true.' This feature is for use with filesystem storage, key value stores, or any other arbitrary-component-id storage systems. When reporting capabilities, it is OPTIONAL to report capabilities that are declared mandatory by the SUIT Manifest . Capabilities defined by extensions MUST be reported. Additional capability reporting can be added as follows: if a manifest element does not exist in this map, it can be added by specifying the CBOR path to the manifest element in an array and using this as the key. For example SUIT_Dependencies, as described in could have an extension added, which was key 3 in the SUIT_Dependencies map. This capability would be reported as: [3, 3, 1] => [3], where the key consists of the key for SUIT_Manifest (3), the key for SUIT_Common (3), and the key for SUIT_Dependencies (1). Then the value indicates that this manifest processor supports the extension (3).

EAT Claim The SUIT_Report is a form of measurement done by the SUIT Manifest Processor as it attempts to invoke a manifest or install a manifest. As a result, the SUIT_Report can be captured in an EAT measurements type. The Verifier MAY convert a SUIT_Report into a more consumable version of the EAT claim by, for example, constructing a measurement results claim that contains the digest of a component, the vendor ID & class ID of a component, etc.

SUIT_Report container The SUIT_Report MUST be carried in a container or transport that ensures authenticity. The SUIT_Report MUST be transported using one of the following options: As an element of an existing document that ensures authenticity, such as in a measurements claim in an EAT (see ). As the payload of a message delivered over secure transport, such as a DTLS , CoAP or Lightweight Machine to Machine message. Contained within a secure container that conforms to the current recommendations of . If a secure container is used, that container MUST be a COSE_Encrypt0 or COSE_Sign1 and SUIT_Report MUST be the sole payload as shown in the CDDL definition fragment below.

any}, payload : bstr .cbor SUIT_Report_Unprotected, signature : bstr ] SUIT_Report_COSE_MAC0_Tagged = #6.17(SUIT_Report_COSE_MAC0) SUIT_Report_COSE_MAC0 = [ protected : bstr, unprotected : {* int => any}, payload : bstr .cbor SUIT_Report_Unprotected, tag : bstr ] SUIT_Report_Unprotected = SUIT_Report / SUIT_Report_COSE_Encrypt0 SUIT_Report_COSE_Encrypt0 = COSE_Encrypt0 ]]>

Note that SUIT_Report_COSE_Sign1 and SUIT_Report_COSE_MAC0 MUST be combined with a SUIT_COSE_Profile from using the CDDL .and directive. The SUIT_Report_COSE_Encrypt0 carries a ciphertext payload that MUST contain just the ciphertext obtained by encrypting the following CDDL:

SUIT_COSE_Profiles define only AES-CTR encryption due to its suitability for firmware distribution. Because AES-CTR is not authenticated, SUIT_Report_Protected defines authenticated containers with an encrypted payload.

IANA Considerations IANA is requested to name the overall SUIT registry group "Software Update for the Internet of Things (SUIT)". IANA is requested to allocate a CBOR tag for each of: SUIT_Report_Protected SUIT_Reference SUIT_Capability_Report IANA is requested to allocate a CoAP content-type and a media-type for SUIT_Report. IANA is also requested to add the following registries to the SUIT registry group: SUIT_Report Elements SUIT_Record Elements SUIT_Report Reasons SUIT Capability Report Elements For each of these registries, registration policy is: -256 to 255: Standards Action -65536 to 257, 256 to 65535: Specification Required -4294967296 to -65537, 65536 to 4294967295: First Come, First Served

Expert Review Instructions The IANA registries established in this document allow values to be added based on expert review. This section gives some general guidelines for what the experts should be looking for, but they are being designated as experts for a reason, so they should be given substantial latitude. Expert reviewers should take into consideration the following points: Point squatting should be discouraged. Reviewers are encouraged to get sufficient information for registration requests to ensure that the usage is not going to duplicate one that is already registered, and that the point is likely to be used in deployments. The zones tagged as private use are intended for testing purposes and closed environments; code points in other ranges should not be assigned for testing. Specifications are required for the standards track range of point assignment. Specifications should exist for all other ranges, but early assignment before a specification is available is considered to be permissible. When specifications are not provided, the description provided needs to have sufficient information to identify what the point is being used for. Experts should take into account the expected usage of fields when approving point assignment. The fact that there is a range for standards track documents does not mean that a standards track document cannot have points assigned outside of that range. The length of the encoded value should be weighed against how many code points of that length are left, the size of device it will be used on, and the number of code points left that encode to that size.

Media Type Registration

application/suit-report+cose

Type name:

application

Subtype name:

suit-report+cose

Required parameters:

n/a

Encoding considerations:

binary (CBOR)

Security considerations:

of &SELF;

Interoperability considerations:

n/a

Published specification:

&SELF;

Applications that use this media type:

SUIT Manifest Processor, SUIT Manifest Distributor, SUIT Manifest Author, RATS Attesters, RATS Verifiers

Fragment identifier considerations:

The syntax and semantics of fragment identifiers are as specified for "application/cose".

Person & email address to contact for further information:

SUIT WG mailing list (suit@ietf.org)

Intended usage:

COMMON

Restrictions on usage:

none

Author/Change controller:

IETF

Provisional registration:

no

CoAP Content-Format Registration IANA is requested to assign a CoAP Content-Format ID for the CoSWID media type in the "CoAP Content-Formats" sub-registry, from the "IETF Review or IESG Approval" space (256..999), within the "CoRE Parameters" registry : Media type Encoding ID Reference application/suit-report+cose cbor+cose TBA &SELF;

CBOR Tag Registration IANA is requested to allocate a tag in the "CBOR Tags" registry , preferably in the Specification Required range: Tag Data Item Semantics TBA array SUIT_Report_Protected TBA map SUIT_Reference TBA map SUIT_Capability_Report

SUIT_Report Elements IANA is requested to create a new registry for SUIT_Report Elements. Label Name Reference 2 Nonce 3 Records 4 Result 5 Result Code 6 Result Record 7 Result Reason 8 Capability Report 99 Reference

SUIT_Record Elements IANA is requested to create a new registry for SUIT_Record Elements. Label Name Reference 0 Manifest ID 1 Manifest Section 2 Section Offset 3 Component Index 4 Dependency Index 5 Record Properties

SUIT_Report Reasons IANA is requested to create a new registry for SUIT_Report Reasons. Label Name Reference 0 Result OK 1 CBOR Parse Failure 2 Unsupported COSE Structure or Header 3 Unsupported COSE Algorithm 4 Signature / MAC verification failed 5 Unsupported SUIT Command 6 Unsupported SUIT Component 7 Unauthorized SUIT Component 8 Unsupported SUIT Parameter 9 Severing Unsupported 10 Condition Failed 11 Operation Failed

 SUIT Capability Report Elements IANA is requested to create a new registry for SUIT Capability Report Elements. Label Name Reference 1 Components 2 Commands 3 Parameters 4 Cryptographic Algorithms 5 Envelope Elements 6 Manifest Elements 7 Common Elements 8 Text Elements 9 Component Text Elements

Security Considerations There are two aspects to the security considerations for SUIT_Reports: authenticity and confidentiality. SUIT_Reports must have guaranteed authenticity for them to be useful. Several options are available to ensure the authenticity of a SUIT_Report. The report MAY be bundled as the payload of a cryptographic container as described in . communicated over a secure transport. It may also be communicated as part of an existing authenticated protocol, such as within an EAT token. Ideally, the SUIT_Report SHOULD be communicated as part of an attestation flow, such as within an EAT token, since this proves the authenticity of the environment (hardware, software, or both) in which the SUIT_Report was generated. The SUIT_Report MAY require confidentiality as well. A SUIT_Report could potentially reveal confidential information about the kinds of device that a particular user has. It could also reveal confidential information about intellectual property contained in a device. Where these concerns are relevant, the SUIT_Report MUST be encrypted, for example using a COSE_Encrypt as described in , or by using secure transport. When reporting failures, particularly in the cryptographic primitives, reporting can increase an attacker's insight into exploitable weaknesses and vulnerabilities. Therefore, SUIT_Reports SHOULD be encrypted wherever possible. There are also operational considerations that intersect with these security considerations. In situations where the SUIT_Report is encrypted as an element of a message within another protocol, care must be taken to ensure that this does not leak information and that the principle of least privilege is respected. For example, in an EAT-based attestation workflow, the Verifier often will not need the full SUIT_Report. Similarly, the Relying Party may also not need the SUIT_Report. To enable the principle of least privilege in this and similar scenarios, the SUIT_Report should be independently encrypted even if the EAT token or encrypted transport that contains it is also encrypted. In contrast, however, there are scenarios where the EAT Verifier consumes the SUIT_Report and translates it into one or more other EAT claims. For example, a SUIT_Report that shows a particular digest was matched using an suit-condition-image can be translated into a EAT measres (Measurement Results) claim. In this scenario, the Verifier must have access to the full SUIT_Report.

Acknowledgements The authors would like to thank Dave Thaler for his feedback.

Arm Limited University of Applied Sciences Bonn-Rhein-Sieg Fraunhofer SIT Inria Nordic Semiconductor This specification describes the format of a manifest. A manifest is a bundle of metadata about code/data obtained by a recipient (chiefly the firmware for an Internet of Things (IoT) device), where to find the code/data, the devices to which it applies, and cryptographic information protecting the manifest. Software updates and Trusted Invocation both tend to use sequences of common operations, so the manifest encodes those sequences of operations, rather than declaring the metadata. Concise Binary Object Representation (CBOR) is a data format designed for small code size and small message size. There is a need to be able to define basic security services for this data format. This document defines the CBOR Object Signing and Encryption (COSE) protocol. This specification describes how to create and process signatures, message authentication codes, and encryption using CBOR for serialization. This specification additionally describes how to represent cryptographic keys using CBOR. This document, along with RFC 9053, obsoletes RFC 8152. An Entity Attestation Token (EAT) provides an attested claims set that describes the state and characteristics of an entity, a device such as a smartphone, an Internet of Things (IoT) device, network equipment, or such. This claims set is used by a relying party, server, or service to determine the type and degree of trust placed in the entity. An EAT is either a CBOR Web Token (CWT) or a JSON Web Token (JWT) with attestation-oriented claims. Arm Limited Nordic Semiconductor Openchip & Software Technologies, S.L. This document specifies cryptographic algorithm profiles to be used with the Software Updates for Internet of Things (suit) manifest. These profiles define mandatory-to-implement algorithms to ensure interoperability. IANA IANA In many standards track documents several words are used to signify the requirements in the specification. These words are often capitalized. This document defines these words as they should be interpreted in IETF documents. This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. RFC 2119 specifies common key words that may be used in protocol specifications. This document aims to reduce the ambiguity by clarifying that only UPPERCASE usage of the key words have the defined special meanings. Fraunhofer SIT arm arm Intel Huawei Technologies Remote Attestation Procedures (RATS) enable Relying Parties to assess the trustworthiness of a remote Attester and therefore to decide whether to engage in secure interactions with it. Evidence about trustworthiness can be rather complex and it is deemed unrealistic that every Relying Party is capable of the appraisal of Evidence. Therefore that burden is typically offloaded to a Verifier. In order to conduct Evidence appraisal, a Verifier requires not only fresh Evidence from an Attester, but also trusted Endorsements and Reference Values from Endorsers and Reference Value Providers, such as manufacturers, distributors, or device owners. This document specifies Concise Reference Integrity Manifests (CoRIM) that represent Endorsements and Reference Values in CBOR format. Composite devices or systems are represented by a collection of Concise Module Identifiers (CoMID) and Concise Software Identifiers (CoSWID) bundled in a CoRIM document. Arm Limited SECOM CO., LTD. This specification describes extensions to the SUIT Manifest format for use in deployments with multiple trust domains. A device has more than one trust domain when it enables delegation of different rights to mutually distrusting entities for use for different purposes or Components in the context of firmware or software update. Fraunhofer SIT Microsoft Research Microsoft Research ARM DataTrails Traceability in supply chains is a growing security concern. While verifiable data structures have addressed specific issues, such as equivocation over digital certificates, they lack a universal architecture for all supply chains. This document proposes a scalable architecture for single-issuer signed statement transparency applicable to any supply chain. It ensures flexibility, interoperability between different transparency services, and compliance with various auditing procedures and regulatory requirements. In network protocol exchanges, it is often useful for one end of a communication to know whether the other end is in an intended operating state. This document provides an architectural overview of the entities involved that make such tests possible through the process of generating, conveying, and evaluating evidentiary Claims. It provides a model that is neutral toward processor architectures, the content of Claims, and protocols. Open Mobile Alliance This document specifies version 1.3 of the Datagram Transport Layer Security (DTLS) protocol. DTLS 1.3 allows client/server applications to communicate over the Internet in a way that is designed to prevent eavesdropping, tampering, and message forgery. The DTLS 1.3 protocol is based on the Transport Layer Security (TLS) 1.3 protocol and provides equivalent security guarantees with the exception of order protection / non-replayability. Datagram semantics of the underlying transport are preserved by the DTLS protocol. This document obsoletes RFC 6347. The Constrained Application Protocol (CoAP) is a specialized web transfer protocol for use with constrained nodes and constrained (e.g., low-power, lossy) networks. The nodes often have 8-bit microcontrollers with small amounts of ROM and RAM, while constrained networks such as IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs) often have high packet error rates and a typical throughput of 10s of kbit/s. The protocol is designed for machine- to-machine (M2M) applications such as smart energy and building automation. CoAP provides a request/response interaction model between application endpoints, supports built-in discovery of services and resources, and includes key concepts of the Web such as URIs and Internet media types. CoAP is designed to easily interface with HTTP for integration with the Web while meeting specialized requirements such as multicast support, very low overhead, and simplicity for constrained environments.

Full CDDL In order to create a valid SUIT_Report document the structure of the corresponding CBOR message MUST adhere to the following CDDL data definition. 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 . It must also have the CDDL from appended to it.

any}, payload : bstr .cbor SUIT_Report_Unprotected, signature : bstr ] SUIT_Report_COSE_MAC0_Tagged = #6.17(SUIT_Report_COSE_MAC0) SUIT_Report_COSE_MAC0 = [ protected : bstr, unprotected : {* int => any}, payload : bstr .cbor SUIT_Report_Unprotected, tag : bstr ] SUIT_Report_Unprotected = SUIT_Report / SUIT_Report_COSE_Encrypt0 SUIT_Report_COSE_Encrypt0 = COSE_Encrypt0 SUIT_Report = { suit-reference => SUIT_Reference, ? suit-report-nonce => bstr, suit-report-records => [ * SUIT_Record / system-property-claims ], suit-report-result => true / { suit-report-result-code => int, suit-report-result-record => SUIT_Record, suit-report-result-reason => SUIT_Report_Reasons, }, ? suit-report-capability-report => SUIT_Capability_Report, $$SUIT_Report_Extensions } SUIT_Reference = [ suit-report-manifest-uri : tstr, suit-report-manifest-digest : SUIT_Digest ] SUIT_Record = [ suit-record-manifest-id : [* uint ], suit-record-manifest-section : int, suit-record-section-offset : uint, suit-record-component-index : uint, suit-record-properties : {*$$SUIT_Parameters}, $$SUIT_Record_Extensions ] system-property-claims = { system-component-id => SUIT_Component_Identifier, + $$SUIT_Parameters, } SUIT_Capability_Report = { suit-component-capabilities => [+ SUIT_Component_Capability] suit-command-capabilities => [+ int], suit-parameters-capabilities => [+ int], suit-crypt-algo-capabilities => [+ int], ? suit-envelope-capabilities => [+ int], ? suit-manifest-capabilities => [+ int], ? suit-common-capabilities => [+ int], ? suit-text-capabilities => [+ int], ? suit-text-component-capabilities => [+ int], ? suit-dependency-capabilities => [+ int], * [+int] => [+ int], $$SUIT_Capability_Report_Extensions } SUIT_Component_Capability = [*bstr,?true] suit-report-nonce = 2 suit-report-records = 3 suit-report-result = 4 suit-report-result-code = 5 suit-report-result-record = 6 suit-report-result-reason = 7 suit-report-capability-report = 8 suit-reference = 99 system-component-id = 0 suit-record-manifest-id = 0 suit-record-manifest-section = 1 suit-record-section-offset = 2 suit-record-component-index = 3 suit-record-dependency-index = 4 suit-record-properties = 5 SUIT_Report_Reasons /= suit-report-reason-ok SUIT_Report_Reasons /= suit-report-reason-cbor-parse SUIT_Report_Reasons /= suit-report-reason-cose-unsupported SUIT_Report_Reasons /= suit-report-reason-alg-unsupported SUIT_Report_Reasons /= suit-report-reason-unauthorised SUIT_Report_Reasons /= suit-report-reason-command-unsupported SUIT_Report_Reasons /= suit-report-reason-component-unsupported SUIT_Report_Reasons /= suit-report-reason-component-unauthorised SUIT_Report_Reasons /= suit-report-reason-parameter-unsupported SUIT_Report_Reasons /= suit-report-severing-unsupported SUIT_Report_Reasons /= suit-report-reason-condition-failed SUIT_Report_Reasons /= suit-report-reason-operation-failed suit-report-reason-ok = 0 suit-report-reason-cbor-parse = 1 suit-report-reason-cose-unsupported = 2 suit-report-reason-alg-unsupported = 3 suit-report-reason-unauthorised = 4 suit-report-reason-command-unsupported = 5 suit-report-reason-component-unsupported = 6 suit-report-reason-component-unauthorised = 7 suit-report-reason-parameter-unsupported = 8 suit-report-severing-unsupported = 9 suit-report-reason-condition-failed = 10 suit-report-reason-operation-failed = 11 suit-component-capabilities = 1 suit-command-capabilities = 2 suit-parameters-capabilities = 3 suit-crypt-algo-capabilities = 4 suit-envelope-capabilities = 5 suit-manifest-capabilities = 6 suit-common-capabilities = 7 suit-text-capabilities = 8 suit-text-component-capabilities = 9 suit-dependency-capabilities = 10 ]]>