SPDX vs CycloneDX

Software Bills of Materials (SBOMs) are critical for managing software transparency and security. Provides a structured approach to capture and communicate details about software components, including their origin, license, and potential vulnerabilities.

Each SBOM format has specific strengths and use cases:

• SPDX
• CycloneDX

SPDX (Software Package Data Exchange): A mature and comprehensive SBOM format designed for detailed software component descriptions, offering a rich vocabulary to capture information such as licenses, copyrights, and relationships between components.

Sample SPDX Format:

{
  "SPDXID": "SPDXRef-Package-A",
  "name": "example-lib",
  "versionInfo": "1.2.3",
  "downloadLocation": "https://example.com/example-lib-1.2.3.tgz",
  "licenseConcluded": "Apache-2.0",
  "checksums": [
    { "algorithm": "SHA256", "checksumValue": "abc123..." }
  ]
}

CycloneDX: A lightweight and user-friendly SBOM format that emphasizes simplicity, focusing on essential component data including identification, versioning, and vulnerabilities.

Sample CycloneDX Format:

{
  "bomFormat": "CycloneDX",
  "specVersion": "1.6",
  "components": [
    {
      "type": "library",
      "name": "example-lib",
      "version": "1.2.3",
      "purl": "pkg:npm/example-lib@1.2.3",
      "hashes": [
        { "alg": "SHA-256", "content": "abc123..." }
      ]
    }
  ],
  "dependencies": [
    { "ref": "pkg:npm/example-lib@1.2.3", "dependsOn": [] }
  ]
}

SBOM Formats Comparison: SPDX vs CycloneDX

Factor	SPDX	CycloneDX
Maintainer	Linux Foundation	OWASP
Supported Formats	Tag/Value, JSON, XML, YAML, RDF	JSON, XML, protobuf
Focus Area	Legal compliance, licensing, and IP due diligence with detailed file and package metadata	Security and vulnerability tracking with strong support for dependency trees and VEX
License Metadata	Extensive license expression support using SPDX license list	Basic license information; includes SPDX identifiers but less detailed
Vulnerability Handling	Relies on external tools for vulnerability mapping	Native support for vulnerability data, VEX, hashing, and dependency relationships
Limitations	Less suited for automated vulnerability tracking; weaker dependency modeling	Less suited for legal/IP compliance; limited licensing detail
Ideal Use Case	Compliance audits, IP due diligence, detailed SBOM report	Security-focused SBOMs, vulnerability tracking, supply chain risk analysis

FAQs: SPDX vs CycloneDX

Which SBOM format should I choose for security scanning?

CycloneDX is better suited for security-focused use cases because it natively supports VEX, hashing, and dependency trees.

Which SBOM format is better for license compliance audits?

SPDX is the preferred choice for legal teams, IP due diligence, and licensing compliance due to its extensive license expression support.

Do both formats support all programming languages and package ecosystems?

Both formats support major ecosystems such as npm, Maven, PyPI, Ruby, Go packages, and more. Support may vary depending on the SBOM generation tool.