Cryptographic Bill of Materials: The CBOM To The Industry’s SBOM

A Cryptographic Bill of Materials (CBOM) is exactly what it sounds like: an inventory of every cryptographic component used throughout an organization. If a Software Bill of Materials (SBOM) tells you what software you have, a CBOM tells you how that software is protected.

As organizations prepare for Post-Quantum Cryptography (PQC), many security experts argue that building a CBOM should be the first step. After all, you can’t replace cryptography if you don’t know where it’s being used.

Why a CBOM Matters

Imagine your organization announces that you’re migrating to PQC.

Great.

Now answer these questions:

• Where are you using RSA?
• Which systems use ECC?
• Which applications depend on SHA-1?
• Which certificates expire after 2030?
• Which databases encrypt with AES-128?
• Which VPNs still negotiate vulnerable cipher suites?
• Which APIs rely on TLS 1.2?
• Which third-party vendors embed OpenSSL 1.1?

If the answer is_,_ “Uh…”

…then you need a CBOM.

It’s More Than an Algorithm List

A good CBOM doesn’t simply say:

RSA
ECC
AES
SHA-256

Instead, it captures details such as:

The goal is to answer not only what cryptography exists, but also where, why, and how it’s being used.

Why Post-Quantum Makes This Urgent

Before quantum computing, organizations rarely inventoried their cryptography in detail.

Why?

Because RSA-2048 worked.

ECC worked.

Certificates renewed automatically.

Life was good.

PQC changes everything.

Suddenly security teams must answer questions like:

• Which systems use RSA key exchange?
• Which APIs perform ECDH?
• Which products can’t support larger PQC keys?
• Which vendors already support ML-KEM?
• Which embedded devices can never be upgraded?

Those aren’t cryptographic questions.

They’re inventory questions.

Crypto Agility Starts Here

You’ve probably heard the term crypto agility.

People often think it means_,_ “The ability to replace one algorithm with another.”

That’s true, but you can’t replace what you haven’t found.

A CBOM becomes the foundation for crypto agility.

Inventory
↓
Risk Assessment
↓
Prioritize
↓
Migrate
↓
Validate

Without the inventory, every subsequent step becomes guesswork.

How Do You Build One?

Building a CBOM is part detective work, part archaeology.

Some information can be gathered automatically.

For example:

• Scan TLS endpoints.
• Inventory X.509 certificates.
• Analyze binaries for crypto libraries.
• Inspect source code.
• Examine dependency manifests.
• Query HSMs and cloud KMS platforms.
• Review CI/CD pipelines.
• Parse Kubernetes secrets and certificates.

Other information requires interviewing application owners.

Questions like:

• Why was RSA-1024 chosen?
• Does anyone still use this API?
• Can this appliance be upgraded?
• Who owns this certificate?

You’ll be surprised how often the answer is “Bob knew.”

Bob retired in 2018.

Vendors Matter Too

Your applications aren’t your only concern.

Many organizations depend heavily on:

• Firewalls
• VPN appliances
• Load balancers
• Identity providers
• Databases
• Storage systems
• Cloud services
• SaaS platforms

Each one contains cryptography.

Each one has its own PQC roadmap.

A CBOM should record vendor versions and planned cryptographic support.

Otherwise you’ll eventually discover that your shiny new PQC strategy is blocked by a load balancer that still thinks RSA-2048 is cutting edge.

Isn’t This Just an SBOM?

Not quite.

An SBOM answers, “What software do I have?”

A CBOM answers, “What cryptography do I depend on?”

The two complement each other.

For example:

One tells you what is installed.

The other tells you how trust is established and protected.

Is There a Standard?

Unlike SBOMs — which have mature formats such as SPDX and CycloneDX — CBOMs are still evolving. There isn’t yet a universally adopted industry standard that every vendor emits.

That said, several efforts are moving in this direction:

• CycloneDX has been expanding beyond software components to include cryptographic asset information, and there are active proposals to model keys, certificates, algorithms, and cryptographic dependencies.
• NIST’s National Cybersecurity Center of Excellence (NCCoE) has identified cryptographic inventories as a critical prerequisite for post-quantum migration.
• The Cybersecurity and Infrastructure Security Agency (CISA) has encouraged organizations to identify and inventory cryptographic assets as part of quantum-readiness planning.
• The Cloud Security Alliance (CSA) has published guidance on crypto inventories and crypto agility in the context of quantum-safe migration.

Most organizations today build their CBOM by combining data from:

• SBOMs
• Certificate inventories
• TLS scanners
• Configuration management databases (CMDBs)
• Cloud key management systems
• Source code analysis
• Vendor questionnaires

A cryptographic migration isn’t fundamentally a cryptography problem — it’s an asset management problem.

The organizations that successfully transition to PQC won’t necessarily be the ones with the best mathematicians. They’ll be the ones that know exactly where their cryptography lives, what it’s protecting, who owns it, and how it can be replaced.

In other words, before you can swap out RSA for ML-KEM or ECDSA for ML-DSA, you need to know where RSA and ECDSA are hiding.

And, as anyone who’s ever inherited a twenty-year-old enterprise application knows, they’re usually hiding everywhere.

Is there a spec that defines this?

Short answer: not yet. There is no RFC, ISO standard, NIST standard, or OpenSSF specification that formally defines a Cryptographic Bill of Materials (CBOM) in the same way that SPDX defines an SBOM.

What’s happening instead is that multiple organizations have recognized the need for cryptographic inventories as part of post-quantum migration, and several are working toward interoperable ways to represent that information.

Here are the most relevant efforts.

1. NIST (Strongly Recommends Inventories)

NIST does not define a CBOM format, but it repeatedly stresses that organizations must identify and inventory their cryptographic assets before migrating to post-quantum cryptography.

The key document is:

• NIST IR 8547 — Transition to Post-Quantum Cryptography Standards
• Recommends identifying all cryptographic dependencies.
• Discusses crypto agility.
• Encourages maintaining inventories of cryptographic assets.
• Official: https://csrc.nist.gov/pubs/ir/8547/final

This is probably the closest thing to “official guidance” today.

2. NSA CNSA 2.0

The NSA’s Commercial National Security Algorithm Suite 2.0 guidance similarly recommends organizations inventory cryptographic assets before migration.

It doesn’t define a CBOM format either.

Instead it assumes organizations already know:

• Where RSA is used
• Where ECC is used
• Certificate inventories
• PKI deployments
• VPNs
• HSMs

Official information can be found here.

3. CISA

CISA has published several quantum-readiness documents encouraging organizations to inventory cryptographic systems.

Again, no schema.

Just recommendations.

4. CycloneDX

This is where things become interesting.

CycloneDX is best known as an SBOM specification.

However, the maintainers have begun discussing extensions that describe:

• Certificates
• Keys
• Algorithms
• Trust relationships
• Cryptographic assets

They’re essentially moving toward what many people would recognize as a CBOM.

Today ,it’s not a standalone CBOM standard.

It’s more accurate to describe it as SBOM + “cryptographic metadata.”

5. OWASP

OWASP has several projects discussing:

• Cryptographic inventories
• Crypto agility
• Algorithm discovery

But, no formal specification.

6. Cloud Security Alliance (CSA)

CSA’s PQC working groups discuss:

• Crypto inventories
• Migration planning
• Crypto agility

Again…

No interchange format.

So where did the term “CBOM” come from?

Interestingly, “Cryptographic Bill of Materials” is more of an industry term than a standards term.

You’ll see it used by:

• IBM
• SandboxAQ
• DigiCert
• PQShield
• Keyfactor
• Venafi
• Entrust
• Numerous consulting firms (hi everybody).

Each means approximately the same thing:

A machine-readable inventory of an organization’s cryptographic assets

But each vendor defines it slightly differently.

What would an actual CBOM contain?

If someone wrote an RFC tomorrow, I’d expect something like this:

Asset:
name: Customer Portal

Algorithms:

• RSA-2048
• AES-256-GCM
• SHA-256

Certificates:

• CN=portal.example.com
  issuer=Example CA
  expires=2028

Libraries:

• OpenSSL 3.4.0

Key Exchange:

• ECDHE P-256

Digital Signatures:

• ECDSA P-256

Key Storage:

• AWS KMS

Dependencies:

• nginx
• OpenSSL

Migration Status:
PQ Ready: No

Owner:
Infrastructure Team

That information is precisely what organizations need to answer questions like, “Where are we still using RSA-2048?” or “Which systems depend on ECDSA P-256?”

My prediction

I would be surprised if we don’t see a formal CBOM specification emerge within the next few years. The momentum is there:

• SBOMs became mainstream because of software supply chain security.
• AI is driving work on AI Bills of Materials (AIBOMs).
• PQC migration is creating the same demand for cryptographic transparency.

My guess is that the eventual CBOM will not be an entirely new standard but rather an extension to CycloneDX or SPDX. That would allow organizations to maintain a unified inventory covering software components, cryptographic assets, AI models, and other metadata instead of managing separate “bill of materials” formats for each domain.

Notes

• AI / GenAI / ChatGPT / etc were not used to generate the text of this article.
• ChatGPT was used to generate the images.
• I used em dashes in my writing before the current GenAI wave was a thing. Not planning on changing now.
• Names have been changed to protect the guilty.
• None of the hostnames or users used in examples actually exist.
• Feel free to post any comments or suggestions below.
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• Do not attempt to use any ideas, code, or programs discussed here in a production environment without first testing it in a non-production environment.
• I’m not responsible for the spontaneous combustion of the known universe or anything else bad that happens to you today as a result of your having read this blog post.