SecureSBOM - SBOM Signing FAQ

SBOM Signing is the process of applying a cryptographically verifiable signature to a Software Bill of Materials. This signature allows anyone to confirm that the SBOM:

• Has not been altered or tampered with, and
• Comes from a trusted source

before it is used in downstream processes such as vulnerability management, license compliance checks, technical due diligence, or regulatory reporting.

But the value of signing becomes even more important as SBOMs grow in complexity. Modern software often contains multiple components or sub-artifacts, each with its own SBOM. These individual SBOMs are frequently combined into a larger, aggregated SBOM representing the entire product.

Consider this example:

You maintain a 3-part application, each part with its own SBOM. When releasing a new version, only part 1 changes—parts 2 and 3 remain identical. Without SBOM signing, you would need to regenerate, rescan, and revalidate all three SBOMs every time, even though two of them didn’t change.

However, if each SBOM was already signed and verified, you can:

• Trust the signatures on parts 2 and 3
• Confidently reuse them in the aggregated SBOM
• Avoid unnecessary rebuilding, rescanning, or reprocessing
• Prove at any time that these SBOMs are bit-for-bit identical to the previously signed versions

This approach reduces operational overhead, improves build efficiency, and strengthens supply-chain integrity—especially across large or modular products.

With SecureSBOM, these signatures are standards-aligned, cryptographically strong, and easy to verify, enabling organizations to safely assemble, reuse, and distribute SBOMs at scale.

SBOMs sit at the center of an organization’s component inventory, vulnerability management workflows, license compliance checks, change-management processes, and more. Because so many critical decisions rely on this single document, it is essential that the SBOM is authentic, comes from a trusted source, and has not been tampered with.

Unsigned or unverified SBOMs introduce several threat vectors, including:

• Information hiding: intentionally altering component versions or metadata to hide known vulnerabilities or license conflicts.
• Manipulation or injection: adding, removing, or modifying components to misrepresent the actual software supply chain.
• Source spoofing: presenting an SBOM as coming from a trusted team or pipeline when it did not.
• Integrity erosion over time: SBOMs passed between teams or systems becoming silently modified without detection.

SecureSBOM addresses these threats by ensuring every SBOM can be cryptographically validated, verified against a trusted key, and checked for unauthorized modification before it is used in any security or compliance workflow.

SecureSBOM is the first SBOM-specific signing and verification platform built for enterprise environments. It provides a PKI-driven approach to applying standards-compliant cryptographic signatures to both CycloneDX and SPDX SBOMs—ensuring authenticity, integrity, and trust throughout your software supply chain.

Designed as a scalable, secure, multi-tenant, API-driven service, SecureSBOM supports:

• HSM-backed key storage for strong, enterprise-grade key protection
• Specification-aligned CycloneDX signing, including proper canonicalization
• Online and offline verification, ideal for clean-room or air-gapped environments
• CI/CD integrations, including GitHub and other DevSecOps tooling
• Modular workflows that support SBOM reuse, aggregation, and enterprise compliance requirements

Sigstore is widely regarded as the de-facto standard for open-source signing and verification workflows. It is an outstanding technology—one we actively use at ShiftLeftCyber in our own CI/CD pipelines. However, despite its strengths, Sigstore has several limitations when it comes to enterprise-grade SBOM signing, which was ultimately one of the motivations to the creation of SecureSBOM.

Key differences include:

• Designed primarily for open-source and OCI artifacts: Sigstore excels at signing container images and verifying them before deployment. Its architecture and tooling are optimized around OCI registries—not SBOM-specific workflows.
• SBOMs are treated as generic files: Sigstore does not adhere to the CycloneDX Signing & Authenticity specification. It simply signs the SBOM as a blob, without respecting canonicalization rules or embedding signatures the way enterprise SBOM ecosystems expect.
• Transparency logs may expose metadata: Sigstore’s default model involves publishing signing metadata to the Rekor transparency log. While acceptable—and even beneficial—for many open-source projects, this can be a blocker for enterprises with strict confidentiality, regulatory, or internal governance requirements. (Note: Cosign v3 disables Rekor by default, but organizations can still enable it, and many workflows rely on it.)
• Complex and costly to operate privately: Running a private Sigstore stack is non-trivial. It requires a multi-service Kubernetes deployment, hardware and operational overhead, long-term maintenance, and expertise—making it impractical for many organizations wanting an internal signing service.

SecureSBOM was built to focus specifically on SBOM authenticity, support CycloneDX-native signing, and provide a lightweight, enterprise-friendly alternative for organizations who want the benefits of signing without the infrastructure burden. For a more detailed compairson between SecureSBOM and Sigstore please see the following

SBOM signing and verification may seem simple on the surface, but in practice it involves several technical and operational challenges. These challenges are amplified in enterprise environments where accuracy, repeatability, and auditability matter.

Here are some of the most common issues:

Non-deterministic formats (JSON & XML)

SBOMs are often represented as JSON or XML—both of which are non-deterministic formats. Whitespace changes, field ordering, or formatting differences can break signature verification even when the SBOM content is logically identical.

SecureSBOM solves this through a standards-aligned canonicalization process, ensuring every SBOM is normalized before signing so verification remains consistent and predictable.

PKI & key management complexity

Managing keys in a PKI system is notoriously difficult. Organizations must handle:

• Key generation
• Secure storage
• Rotations
• Revocations
• Access control
• Audit logs
• Compliance requirements

SecureSBOM removes this burden by providing fully managed, HSM-backed key infrastructure, so teams never have to maintain sensitive key material or operate their own PKI.

Complex, error-prone verification workflows

Verifying an SBOM manually often requires messy combinations of tooling such as:

• OpenSSL
• jq
• Custom scripts
• Vendor-specific CLI utilities

This leads to inconsistency across teams and makes it difficult to standardize verification policies.

SecureSBOM offers simple online APIs, a fully offline verification tool, & numrious intrgrations with GitHub and other 3rd party tools making verification consistent across environments—including air-gapped or clean-room builds.

SBOM aggregation & reuse becomes complicated without signatures

Large products often consist of many subcomponents, each with its own SBOM. Without signatures, it is impossible to safely reuse or merge previously generated SBOMs.

With SecureSBOM, previously signed SBOMs can be verified and reused, dramatically reducing build times, rescan overhead, and reprocessing costs.

Enterprise confidentiality concerns around transparency logs

Sigstore was designed for open-source ecosystems, where openness and public transparency are strengths. However, this model creates two major challenges for enterprises:

Transparency logs (like Rekor) may expose signing metadata that internal teams or regulated industries cannot publicly disclose. Even though Cosign v3 disables Rekor by default, many workflows still rely on it, and enabling it reintroduces the same concerns.

Private Sigstore deployments are complex and costly. Running Sigstore internally requires a Kubernetes cluster, multiple coordinated services, storage backends, and ongoing operational maintenance—making it difficult for many organizations to adopt privately.

SecureSBOM avoids these challenges by offering a fully private, API-first signing service that requires no infrastructure management and exposes no metadata publicly, providing the security guarantees enterprises need without the operational overhead.

SBOM signing isn’t just adding a signature—it requires deterministic formatting, proper spec compliance, key management, verification tooling, and enterprise controls. SecureSBOM wraps all of this into a purpose-built, SBOM-first solution.

SecureSBOM ensures that every SBOM you produce or consume is authentic, trusted, and verifiably unmodified. It solves the core challenges of SBOM signing and verification by providing:

• Standards-compliant, deterministic signing for both CycloneDX and SPDX
• HSM-backed key management, removing the burden of running your own PKI
• Simple online and offline verification tools, eliminating fragile OpenSSL/jq workflows
• Safe SBOM reuse and aggregation, enabling faster builds and reduced processing overhead
• Enterprise privacy and control, with no public transparency logs or external exposure
• Turnkey integrations with GitHub and common CI/CD platforms

By combining these capabilities, SecureSBOM gives organizations a secure, scalable, SBOM-first signing solution that improves trust, reduces operational friction, and strengthens software supply chain integrity end-to-end.