What Is a Cryptographic Bill of Materials (CBOM)?

Definition of CBOM

A CBOM describes the cryptographic elements of a system or product. It typically includes:

• encryption and signature algorithms
• digital certificates and key material
• cryptographic libraries
• security protocols
• hash functions
• security-relevant configuration parameters

A CBOM enables clear documentation of which cryptographic mechanisms are used and in what form.

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Components of CBOM

Depending on the system, CBOMs may include:

1. Algorithms and Methods

Documentation of encryption and signature algorithms.

2. Certificates and PKI Elements

Validity periods, issuers, and usage contexts.

3. Key Material

Key types, strengths, and storage locations.

4. Cryptographic Libraries

Examples include OpenSSL or proprietary vendor stacks.

5. Protocols and Configurations

Protocol versions, cipher suites, and relevant security settings.

6. Context and Lifecycle Information

Usage locations, dependencies, and responsible parties.

7. Alignment with established formats such as CycloneDX

The open-source project CycloneDX provides a standardized format that supports the representation of cryptographic materials. Its CBOM capability defines a structured way to describe cryptographic elements within software or devices.

CycloneDX specifies only the data model. It does not prescribe organizational requirements or imply regulatory obligations.

Organizations may use this format to document and exchange cryptographic information in a consistent manner.

Importance of CBOM for Organizations

Documenting cryptographic elements offers several practical advantages:

• Transparency:

Clear overview of the cryptographic components in use.

• Risk assessment:

Identification of outdated or insecure elements.

• Structured management:

Support for handling certificates, keys, and configurations.

• Support for security evaluations:

Well-organized information for audits, internal assessments, or technical reviews.

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A CBOM provides the technical basis for evaluating cryptographic security and understanding system dependencies.

Relevance for Industrial & OT Environments

In OT systems, cryptographic components are often distributed across multiple devices and systems. Many industrial assets have long life cycles and contain proprietary or tightly integrated cryptography.

A CBOM can support:

documenting cryptography used in controllers, sensors, and communication components

• comparing different cryptographic versions across heterogeneous machine fleets
• preparing information for technical security evaluations
• understanding certificate and key structures

‍Example from manufacturing:

A production environment contains equipment from several vendors, each using different cryptographic components. A CBOM helps document these differences and supports structured security assessments.

Typical Challenges

Challenges in creating CBOMs include:

cryptographic information distributed across different systems

• limited visibility into OT devices
• lack of centralized documentation
• heterogeneous vendor formats and libraries
• manual collection effort

Using structured data formats such as CycloneDX can help create consistent documentation.

CBOM in the future?

A CBOM is a technical tool for documenting cryptographic elements. As digital systems and supply chains become more complex, consistent and structured documentation becomes increasingly useful. Formats such as CycloneDX offer a standardized basis for representing this information. The specific use of a CBOM depends on an organization’s internal processes, systems, and security requirements. A CBOM itself imposes no security requirements — it describes cryptographic materials only.

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