CX-0161 ECU Crypto Material v1.0.0
ABSTRACT
This standard defines the rules for participating in the ECU Crypto Material use case within the Catena-X ecosystem. It specifies the aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing). for ECU-related cryptographic material, the data exchange (Push Notification or Digital Twin Pull), and the associated policies required to exchange cryptographic material — such as Certificate Signing Requests (CSRs), keys, and certificates — between Data Providers (e.g., ECU suppliersSupplier In the context of OSim, the producer of goods.) and Data Consumers (e.g., OEMs) in a standardized, sovereign, and interoperable manner.
FOR WHOM IS THE STANDARD DESIGNED
This standard is relevant for Data Providers, Data Consumers and Business Application Providers that participate in the ECU Crypto Material use case.
1 INTRODUCTION
There is a growing need for standardized cryptographic information exchange related to Electronic Control Units (ECUs). Such information is required both to verify the authenticity of an ECU and to provide secure access to protected debugging or development functionalities. This use case focuses on establishing a unified format for sharing this sensitive data.
A key benefit arises for ECU manufacturers, who currently must provide similar information to many customersCustomer In the context of OSim, the receiver of produced goods from a supplier., e.g. OEMs (Original Equipment Manufacturer), through different interfaces, models, and interpretations. The lack of uniformity increases effort, complexity, and the risk of miscommunication. By defining a standardized format that can also be supported by Business Application Providers, this approach enables significant harmonization, reduces integration overhead, and improves interoperability across the ecosystem.
1.1 AUDIENCE & SCOPE
This section is non-normative
This standard is relevant for Data Providers, Data Consumers and Business Application Providers.
In scope is the harmonization of data transfer between a Data Provider and a Data Consumer, meaning the data transfer from, e.g. a supplierSupplier In the context of OSim, the producer of goods. (Tier-1) to a customerCustomer In the context of OSim, the receiver of produced goods from a supplier. (OEM). The standard covers:
- The aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing). for CryptoMaterial
- The aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing). for SoftwareInformation
- The notification-based (push) APIAPI An API is a way for two or more computer programs to communicate with each other. for transmitting ECU-related cryptographic material and receiving detailed business feedback
- AssetAsset On the Data Provider side, an Asset describes the data set which will be shared or can be consumed by a Data Consumer. structures and usage policies for sovereign data exchange via Digital Twins
Not in scope is:
- Data transfer or communication between Electronic Control Units (ECU-to-ECU).
- End-to-end payload encryption mechanisms (which must be bilaterally agreed upon by Data Provider and Data Consumer — see Section 1.2.3).
1.2 CONTEXT AND ARCHITECTURE FIT
This section is non-normative
The ECU Crypto Material standard defines a structured data model that enables the exchange of ECU-related cryptographic information. This information is shared between a Data Provider and a Data Consumer.
The architecture allows a pull-based and push-based pattern:
- Data can be pushed from Data Provider to Data Consumer using the notifications according to CX-0151 Industry Core: Basics
- Data can be made accessible by the Data Provider via Digital Twins. Data Consumers query or request the information when needed.
This standalone standard enables harmonized data transfer using common aspect modelsAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing)..
1.2.1 Crypto Material Push
The following sequence diagram illustrates the end-to-end data flow for the ECU Crypto Material push within the Catena-X ecosystem. It shows how ECU-related data is transferred from the provider-side system through the respective connectors to the consumer-side processing system, and how feedback is propagated back to the originator.
The process consists of two feedback phases. The first technical feedback (httpHTTP HTTP is an application-layer protocol for transmitting hypermedia documents (such as HTML). It was designed for communication between web browsers and web servers, but can also be used for other purposes.-response) must be generated automatically. The second business-level feedback is optional.
An initial technical acknowledgement (“received”), confirming that the data has been successfully delivered to the consumer-side processing pipeline.
A subsequent business-level feedback (“accepted” or “rejected”), indicating the actual processing result of the ECU data.
Both feedback messages are propagated transparently through the EDCs or a CX-0018 compatible implementation back to the originating system, ensuring full traceability and synchronization of processing states between provider and consumer.
The term DOS in this context is used as a placeholder for the system that handles the ECU communication on the provider side. This may be a Manufacturing Execution System (MES), but it may equally be any other backend or application component responsible for preparing, sending, receiving, or processing ECU-related data and feedback. This can include a self-managed in-house solution as well as a solution provided and operated by a service provider.
1.2.2 Crypto Material Pull
The following sequence diagram illustrates an example of the end-to-end data flow for the ECU Crypto Material pull within the Catena-X ecosystem. It shows how ECU-related data is obtained by a Data Consumer and connected to a processing system. The Data Consumer SHOULD generate a feedback notification in response to the processing results to inform the Data Provider about the validation result.
1.2.3 Security Considerations
The ECU Crypto Material standard enables the exchange of cryptographic material between a Data Provider and a Data Consumer. Since this material may include secret cryptographic keys, its secure transmission must be considered to maintain confidentiality and integrity, as well as ensure the intended security level of the material.
Catena-X provides secure connector-to-connector communication between Data Provider and Data Consumer using HTTPSHTTP HTTP is an application-layer protocol for transmitting hypermedia documents (such as HTML). It was designed for communication between web browsers and web servers, but can also be used for other purposes.. Data transmitted via HTTPSHTTP HTTP is an application-layer protocol for transmitting hypermedia documents (such as HTML). It was designed for communication between web browsers and web servers, but can also be used for other purposes. is protected through the Transport Layer Security (TLS) protocol (see IETF RFC 9110). The negotiation of the TLS version and cipher suite, as well as the encryption and decryption of the data, are handled by the HTTPSHTTP HTTP is an application-layer protocol for transmitting hypermedia documents (such as HTML). It was designed for communication between web browsers and web servers, but can also be used for other purposes. implementation of each participant's connector.
However, the security provided by connector-to-connector encryption is in many cases insufficient for the transmission of secret cryptographic material. While this protects data in transit between connectors, it does not guarantee confidentiality throughout the entire data path. Connector-to-connector encryption terminates at each participant's connector, meaning that intermediate systems at both the Data Provider's and Data Consumer's side may access secret cryptographic material in plaintext, as it is processed by the connectors and potentially other infrastructure elements.
In addition, the protection mechanism used during transmission must offer a security strength at least equal to the of the cryptographic material itself. Otherwise, the effective security level of the transmitted cryptographic material is reduced (see NIST SP 800-57 Part 1 Rev. 5). Such mismatches may occur because TLS versions and cipher suites differ across participants. TLS 1.3 requires AES-128-GCM (128-bit security), while support for stronger ciphers such as AES-256-GCM or ChaChaPoly1305 (256-bit security) is only recommended (see IETF RFC 8446). Older TLS versions may permit even weaker legacy ciphers that no longer meet modern security requirements.
To ensure continuous confidentiality from the Data Provider's source system to the Data Consumer's destination system, explicit payload-level end-to-end encryption (E2EE) is recommended.
In this approach, the chosen protection mechanism (e.g., RSA key wrapping, KEM-based encryption, PGP) and the required key exchange procedure (e.g., pre-stablished keys or secure out-of band exchange) must be bilaterally agreed upon by the Data Provider and Data Consumer. This offers the flexibility to meet specific security requirements - including security level, algorithm selection, and infrastructure constraints - but also means that while the Catena-X transmission process and the data models are specified in this standard, the E2EE protection itself remains Data Provider-Consumer specific.
1.3 CONFORMANCE AND PROOF OF CONFORMITY
This section is normative
Since this document describes a set of standards to be fulfilled, participants MUST fulfill all normative requirements, such as other Catena-X standards and the respective conformity assessment criteria in addition to the specific criteria mentioned in this document.
To comply with this standard, the following assessment criteria MUST be met:
- The Data Provider / Business Application Provider MUST use the defined aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing).(s) in Section 3.
- Business Application Providers MUST prove their conformity by providing an OpenAPI specification of the notification APIAPI An API is a way for two or more computer programs to communicate with each other. endpoints described in Section 4. A Business Application MUST provide the functionality to receive Feedback. If this functionality is used by the Data Consumer it is OPTIONAL and must be mutually agreed by the Data Provider and Data Consumer.
- The notification data format MUST be compliant with the notification data format defined in Section 4, including the standardized MessageHeader as described in CX-0151 Industry Core: Basics.
- Examples of the data assetAsset On the Data Provider side, an Asset describes the data set which will be shared or can be consumed by a Data Consumer. and contract definition structure in their CX-0018-compliant connector MUST correspond to the described structure in Section 4.2.2.
1.4 EXAMPLES
The benefit of this standard is to provide Aspect ModelsAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing). which harmonize the necessary data to exchange cryptographic material concerning a physical ECU. This enables a common understanding of necessary data attributes and ECU manufacturers can leverage synergies as the same technical architecture and implementation can be used for different customersCustomer In the context of OSim, the receiver of produced goods from a supplier. with only minor adjustments.
Examples for data models: See according subsection Section 3. Examples for APIsAPI An API is a way for two or more computer programs to communicate with each other.: See according subsection Section 4.
1.5 TERMINOLOGY
This section is non-normative
The following terms are especially relevant for the understanding of the standard:
- ECU: Electronic Control Unit — an embedded computer that controls one or more electrical systems or subsystems in a vehicle.
- CSR: Certificate Signing Request — a request sent to a Certificate Authority (CA) to obtain a digital certificate.
- Notification: In Catena-X, notifications are JSON messages with a standardized data format consisting of a standardized header (defined in CX-0151 Industry Core: Basics) and a use-case-specific content.
- Notification APIAPI An API is a way for two or more computer programs to communicate with each other.: A message-based data exchange within Catena-X that supports a set of operations. Each use case defines its own notification APIAPI An API is a way for two or more computer programs to communicate with each other. extending the base notification infrastructure.
- Symmetric Key: A secret key shared between all participants in a symmetric cryptographic scheme.
- Private Key: The private key of an asymmetric key pair.
- Public Key: The public key of an asymmetric key pair.
- Digital Certificate: A digital certificate associating an asymmetric public key with the identity of the certificate's subject.
- Secret Material: Any secret cryptographic material not considered a symmetric key or asymmetric private key (e.g. passwords, seed values).
2 RELEVANT PARTS OF THE STANDARD FOR SPECIFIC USE CASES
This section is normative
2.1 ECU CRYPTO MATERIAL DATA EXCHANGE
2.1.1 LIST OF STANDALONE STANDARDS
To participate in the ECU Crypto Material use case, all participants MUST comply with the following standalone standards:
- CX-0001 Participant Agent Registration v1.2
- CX-0018 Dataspace Connectivity v4.1.1
- CX-0127 Industry Core: Part InstancePart Instance A Part Instance is a physically produced instance (e.g., serialized part, batch, just-in-sequence part) of a Part Type. v2.0.2
- CX-0151 Industry Core: Basics v1.0.0
- CX-0152 Policy Constraints for Data Exchange v1.0.0
2.1.2 DATA REQUIRED
The following data MUST be provided by Data Providers participating in the ECU Crypto Material use case:
-
ECU Identification Data (via SerialPart or JustInSequencePart aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing)., see CX-0127 Industry Core: Part InstancePart Instance A Part Instance is a physically produced instance (e.g., serialized part, batch, just-in-sequence part) of a Part Type.): The serialized ECU MUST be identified by its Global Assset ID (globalAssetId) and local identifiers including manufacturerId (BPNLBPNL The unique identifier of a legal entity of a partner within Catena-X (e.g., a company). of supplierSupplier In the context of OSim, the producer of goods.), partInstanceId, and ecuSerialNumber.
-
ECU Cryptographic Material (via CryptoMaterial aspect model): The cryptographic material associated with the ECU MUST be provided according to the aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing). defined in Section 3.1.
-
ECU Digital Twin Type (see CX-0127 Industry Core: Part InstancePart Instance A Part Instance is a physically produced instance (e.g., serialized part, batch, just-in-sequence part) of a Part Type.): If a Digital Twin is created for an ECU participating in this use case, the Digital Twin MUST represent a PartInstance as defined in CX-0127 Industry Core: Part InstancePart Instance A Part Instance is a physically produced instance (e.g., serialized part, batch, just-in-sequence part) of a Part Type.. The identifiers of the Digital Twin MUST comply with the identification requirements of CX-0127 Industry Core: Part InstancePart Instance A Part Instance is a physically produced instance (e.g., serialized part, batch, just-in-sequence part) of a Part Type..
The following data MAY be provided by Data Providers participating in the ECU Crypto Material use case:
- ECU Software Information (via SoftwareInformation aspect model): The software information associated with the ECU MAY be provided according to the apsect model defined in Section 3.2.
2.1.3 DIGITAL TWINS AND SPECIFIC ASSET IDs
The usage of Digital Twins for ECU data is OPTIONAL for this use case. The push-based notification mechanism (Section 4) does not require Digital Twins. However, if a Digital Twin is created for an ECU (recommended for cross-use-case reusability), the globalAssetId used in notifications MUST match the globalAssetId of the Digital Twin.
If Digital Twins are created for ECUs participating in this use case, the following specific assetAsset On the Data Provider side, an Asset describes the data set which will be shared or can be consumed by a Data Consumer. IDsIDS The International Data Space enables 'smart services' and business processes across companies and industries while ensuring data sovereignty and self-determined control of data use. MUST be provided when registering the Digital Twin (see CX-0127 Industry Core: Basics):
- Key = "ecuSerialNumber": The ECU serial number (OEM-specific serial number format).
Additionally, mandatory and optional specific assetAsset On the Data Provider side, an Asset describes the data set which will be shared or can be consumed by a Data Consumer. IDsIDS The International Data Space enables 'smart services' and business processes across companies and industries while ensuring data sovereignty and self-determined control of data use. of CX-0127 Industry Core: Basics standard apply.
The globalAssetId used for the ECU in this use case MUST match the globalAssetId of that Digital Twin.
2.1.4 POLICY CONSTRAINTS FOR DATA EXCHANGE
In alignment with our commitment to data sovereignty, a specific framework governing the utilization of data within the Catena-X use cases has been outlined. As part of this data sovereignty framework, conventions for access policies, for usage policies and for the constraints contained in the policies have been specified in standard 'CX-0152 Policy Constraints for Data Exchange'. This standard document CX-0152 MUST be followed when providing services or apps for data sharing/consuming and when sharing or consuming data in the Catena-X ecosystem. What conventions are relevant for what roles named in 1.1 AUDIENCE & SCOPE is specified in the CX-0152 standard document as well. CX-0152 can be found in the standard library.
2.1.5 Usage Policy
The "AssetAsset On the Data Provider side, an Asset describes the data set which will be shared or can be consumed by a Data Consumer. for Certificate Notifications" included in the CX-0018 compliant implementation of a data consumer MUST contain a usage policy as specified below. The legal meaning of this usage policy will be defined and added to the CX-0152 Policy Constraints For Data Exchange standard in release 26.09.
The "rightOperand" for the "leftOperand" "UsagePurpose" MUST include the following usage purpose: 'cx.ecu.base:1`.
Additional more general usage policies MAY be included, but all the usage policies MUST contain the above mentioned usage purpose as shown below.
{
"@context": [
"http://www.w3.org/ns/odrl.jsonld",
"https://w3id.org/catenax/2025/9/policy/context.jsonld"
],
"@type": "Set",
"@id": "ecu-usage-policy",
"permission": [
{
"action": "use",
"constraint": {
"and": [
{
"leftOperand": "FrameworkAgreement",
"operator": "eq",
"rightOperand": "DataExchangeGovernance:1.0"
},
{
"leftOperand": "UsagePurpose",
"operator": "isAnyOf",
"rightOperand": "cx.ecu.base:1"
}
]
}
}
]
}
3 ASPECT MODELS
This section is normative
3.1 ASPECT MODEL "CryptoMaterial"
3.1.1 INTRODUCTION
The "CryptoMaterial" aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing). defines a standardized, interoperable representation of the cryptographic material associated with an ECU instance within the Catena-X ecosystem.
Cryptographic material exchanged through this semantic model includes the cryptographic keys and other cryptographic information used to protect ECU data and functionality, verify an ECU part instancesPart Instance A Part Instance is a physically produced instance (e.g., serialized part, batch, just-in-sequence part) of a Part Type.' digital identity, and enable communication with other in-vehicle or backend systems.
The model is designed to flexibly accomodate the diverse cybersecurity concepts used across customersCustomer In the context of OSim, the receiver of produced goods from a supplier., suppliersSupplier In the context of OSim, the producer of goods., and ECU types. It accommodates varying types, quantities, formats and combinations of cryptographic material and does not prescribe a rigid configuration, therefore enabling Catena-X participants to represent their individual ECU security architectures within a consistent semantic framework.
3.1.2 SUPPORTED CRYPTOGRAPHIC MATERIAL, FORMATS AND ENCODING
The following sections define the enumerations of the CryptoMaterial aspect modelAspect Model A formal, machine-readable semantic description (expressed with RDF/Turtle) of data accessible from an aspect. Note 1: An Aspect Model must adhere to the Semantic Aspect Meta Model (SAMM) and be compliant with its validity rules. Note 2: Aspect Models are logical data models that can be used to detail a conceptual model to describe the semantics of runtime data related to a concept; elements of an Aspect Model can/should refer to terms of a standardized Business Glossary (if existing). that specify the type, format, and encoding of cryptographic material. This ensures that Data Consumers can unambiguously interpret the payload received from the Data Provider, and that only values compliant to this standard may be transmitted.
The following table provides an overview of the permitted combinations of cryptographic material types, formats and encodings that MUST be used in compliance with this standard:
| Type | Format | Base64 Encoding | HEX Encoding | RFC 7468 Encoding |
|---|---|---|---|---|
| Symmetric Key | Raw | ✔ | ✔ | ✖ |
| Private Key | PKCS#1 | ✔ | ✔ | ✖ |
| Private Key | PKCS#8 | ✔ | ✔ | ✔ |
| Public Key | PKCS#1 | ✔ | ✔ | ✖ |
| Public Key | PKCS#8 | ✔ |