Standardization, Scope, and Strategic Role

Mehrnoush Vaseghipanah

Abstract

The increasing pervasiveness of cryptography across modern software systems has introduced a critical visibility gap: while Software Bills of Materials (SBOMs) enumerate software components and dependencies, they provide little insight into how cryptography is implemented, configured, or used in practice. This limitation hinders effective cryptographic risk management, regulatory compliance, and large-scale transitions such as post-quantum cryptography (PQC) migration.

A Cryptographic Bill of Materials (CBOM) addresses this gap by providing a machine-readable inventory of cryptographic assets embedded within software systems, including algorithms, modes of operation, protocols, cryptographic libraries, keys, certificates, and their dependency relationships. Building upon the SBOM ecosystem, CBOM extends software transparency from identifying what components are present to understanding what cryptography is used, where it is used, and how it is applied.

This article describes the scope and role of CBOM, analyzes the current state of standardization with a focus on the CycloneDX CBOM specification, and discusses the convergence of earlier initiatives into a largely unified technical framework. It further surveys the emerging tooling landscape, encompassing both open-source and enterprise solutions for CBOM generation, analysis, and operational integration. Finally, the paper positions CBOM as a foundational element of broader cryptographic posture management and PQC readiness strategies, highlighting practical challenges, limitations, and avenues for future work.

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1. Introduction

A Cryptographic Bill of Materials (CBOM) is a structured, machine-readable inventory that documents the cryptographic assets embedded within software systems. These assets include cryptographic algorithms, modes of operation, protocols, cryptographic libraries, keys, certificates, and their relationships to software components and execution contexts. CBOM extends the concept of a Software Bill of Materials (SBOM) by focusing specifically on cryptographic material, enabling organizations to systematically manage cryptographic risk, ensure regulatory compliance, and prepare for large-scale cryptographic transitions such as post-quantum cryptography (PQC) migration.

As cryptography becomes deeply embedded across application stacks, infrastructure, firmware, and cloud services, organizations face a growing visibility gap. While SBOMs provide valuable insight into software composition, they do not capture how cryptography is implemented, configured, negotiated, or invoked at runtime. CBOMs address this limitation by introducing cryptography-specific transparency that is essential for cryptographic agility, vulnerability response, and long-term system resilience.

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2. CBOM Standardization and Industry Convergence

Current evidence indicates a strong—though not absolute—industry convergence around a dominant technical standard for CBOM, driven primarily by the CycloneDX specification. Early CBOM initiatives, most notably IBM’s CBOM project, initially proposed independent schemas and tooling. These efforts have since been contributed upstream and incorporated into CycloneDX, significantly accelerating ecosystem alignment.

CycloneDX, an OWASP project ratified as ECMA-424, incorporates CBOM as a native capability beginning with version 1.6. Rather than defining a standalone artifact, CycloneDX extends the SBOM object model to include cryptographic asset types, crypto-specific properties, and explicit dependency semantics. This approach preserves backward compatibility with existing SBOM pipelines while enabling fine-grained modeling of cryptographic usage and dependencies.

At present, no alternative CBOM formats exhibit comparable levels of adoption, tooling support, or cross-industry interoperability. However, it is important to note that in certain highly specialized domains—such as classified national security systems, proprietary embedded platforms, or legacy industrial environments—internal or domain-specific cryptographic inventories may still exist. These formats are typically non-public and lack standardized interchange mechanisms. Consequently, CycloneDX currently represents the only broadly adopted and interoperable foundation for CBOM generation, exchange, and analysis in open and commercial ecosystems.

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3. CBOM and SBOM: Conceptual Relationship and Distinction

CBOM should not be interpreted as a replacement for SBOM, but rather as a cryptography-focused extension that builds upon SBOM foundations. The relationship between the two artifacts is complementary and hierarchical.

Table 1. Comparison of SBOM and CBOM

Aspect	Software Bill of Materials (SBOM)	Cryptographic Bill of Materials (CBOM)
Primary Focus	Inventory of software components and dependencies (packages, libraries, modules).	Inventory of cryptographic assets within software components.
Typical Contents	Component names, versions, suppliers, licenses, dependency graphs.	Algorithms, key sizes, certificates, cryptographic libraries, protocols, cipher suites.
Core Purpose	Software supply-chain transparency; vulnerability and license management.	Cryptographic risk management; detection of weak or deprecated crypto; PQC readiness.
Relationship	Foundational inventory layer.	Extends SBOM with crypto-specific metadata and relationships.

In practical deployments, an SBOM identifies where cryptography could exist, while a CBOM specifies what cryptography actually exists and how it is used. Without an SBOM, CBOM lacks software context; without a CBOM, SBOM lacks cryptographic meaning.

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4. CBOM Data Model and Contents (CycloneDX-Aligned)

A CBOM provides a structured representation of cryptographic assets using CycloneDX’s extended object model. It is designed to be machine-readable (JSON or XML) and suitable for automated analysis, policy enforcement, and lifecycle management.

4.1 Cryptographic Asset Types

A standard CBOM typically includes the following categories:

• Algorithms and Modes
  Explicit identification of cryptographic primitives and constructions, such as AES-256-GCM, RSA-2048, SHA-256, or ML-DSA, including modes of operation, padding schemes, and security parameters.
• Cryptographic Libraries and Implementations
  References to libraries (e.g., OpenSSL, Bouncy Castle, liboqs), including versions and implementation characteristics (software, hardware, FIPS-validated, etc.).
• Keys and Certificates (Metadata Only)
  Descriptive metadata about keys and certificates—type, size, algorithm, format, issuer, validity period, and lifecycle state—without including secret key material.
• Protocols and Cipher Suites
  Protocols such as TLS (including version and negotiated cipher suites), SSH, IPsec, or custom protocols, including version information, negotiated cipher suites, and their underlying cryptographic dependencies.
• Usage Context and Relationships
  Explicit linkage between cryptographic assets and software components or services, using relationship semantics such as:
• implements: cryptography available within a component or library
• uses: cryptography actively invoked by an application or configuration

This distinction enables CBOMs to differentiate between cryptographic capability and effective cryptographic usage, which is critical for accurate risk assessment.

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5. Generation and Integration into Security Workflows

CBOMs are not intended to be static documentation artifacts. Instead, they are designed to be continuously generated and consumed as part of modern software and security workflows.

5.1 Generation Methods

CBOMs can be generated through a combination of:

• Static source code analysis, identifying cryptographic APIs, parameters, and call sites
• Binary and container analysis, extracting embedded cryptographic libraries, configurations, and certificates
• Build and CI/CD integration, producing CBOMs as versioned artifacts alongside SBOMs

Open-source toolchains such as CBOMkit and CycloneDX tooling support automated CBOM generation and validation. Nevertheless, practical challenges remain, including analysis of obfuscated code, detection of proprietary or custom cryptographic implementations, and scalability concerns when analyzing large, heterogeneous system portfolios.

5.2 Core Use Cases

Key operational use cases include:

• Post-Quantum Cryptography (PQC) Migration
  CBOMs provide the essential inventory required to identify classical public-key cryptography and prioritize migration to quantum-resistant or hybrid schemes.
• Cryptographic Vulnerability Management
  When cryptographic weaknesses or deprecations are announced (e.g., SHA-1, RSA-1024, TLS 1.0), CBOMs enable rapid identification of affected systems and components.
• Compliance and Audit Support
  CBOMs serve as verifiable evidence of cryptographic practices for regulatory and standards frameworks such as NIST guidance, FIPS 140-3, PCI DSS, and government mandates requiring cryptographic inventories.

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6. Strategic Role of CBOM in Cryptographic Posture Management

While a CBOM provides a comprehensive static view of cryptographic assets embedded in software, it does not, by itself, capture the full cryptographic risk posture of an organization. Actual risk is influenced by operational factors such as runtime configurations, deployment environments, key management practices, and protocol negotiation behavior.

In practice, CBOM data can be combined with organizational policy frameworks to support contextual risk evaluation. For example, a policy may classify the use of RSA-2048 for digital signatures in an internal legacy system as moderate risk, while the same algorithm deployed in internet-facing critical infrastructure may be classified as high risk due to exposure and long-term confidentiality requirements. Such evaluations demonstrate how CBOM serves as an enabling input to higher-level risk scoring and decision-making processes.

Accordingly, CBOM should be understood as a foundational layer within a broader cryptographic posture management strategy, where its value is maximized when enriched with runtime discovery, policy enforcement, lifecycle management, and risk prioritization mechanisms.

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7. Summary

The industry is converging toward CycloneDX CBOM as the primary interoperable standard for representing cryptographic assets within software systems, while acknowledging that limited domain-specific alternatives may persist in specialized environments. By extending SBOM concepts with cryptography-specific semantics, CBOM provides the visibility necessary to manage cryptographic risk, respond to vulnerabilities, demonstrate compliance, and plan for post-quantum transitions. When integrated into modern development and security workflows, CBOM becomes a critical enabler of cryptographic agility and long-term resilience.

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References

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