Embedded Systems Discovery

What embedded-systems discovery means

Embedded-systems discovery is a cryptographic inventory activity focused on devices whose security-relevant functions may be distributed across hardware, firmware, boot code, operating-system components, applications, communication protocols, manufacturing steps, and fleet operations. The object of discovery is therefore broader than a source-code search or an endpoint scan. Public-key cryptography can be integrated into hardware, operating systems, application programs, databases, communications protocols, key infrastructures, and access-control mechanisms. C011

A useful finding answers four questions: where is cryptography present; what algorithm, primitive, library, module, key, certificate, or protocol is involved; why is it used; and which device models, software versions, manufacturing lots, environments, or fleet populations depend on it. Examples of purposes include digital signatures for source authentication and integrity, identity authentication for establishing sessions or authorizing actions, and key transport for symmetric keys or other keying material. [C06]1

Evidence to collect

Begin with a documented evidence plan covering the device and the systems that create, provision, update, configure, communicate with, and retire it. The following sources should be correlated rather than treated as interchangeable. Their relevance will vary by product architecture, and the source set does not establish that every source exists for every device. C011

• Firmware and boot chain: collect release images, bootloaders, recovery images, manifests, signing metadata, version identifiers, and documented verification steps. Secure or measured boot can establish a chain of trust from hardware through bootloaders and operating-system components, enabling cryptographic verification of boot mechanisms and system images. [C10]
• Update packages and release artifacts: examine package formats, signing certificates, signature algorithms, key identifiers, rollback or version controls, and the build-to-release path. Integrity protection for installation and update is an explicit security function in software vetting, and image-integrity mechanisms can detect unauthorized changes. C11
• Hardware security elements: document roots of trust, trusted key storage, cryptographic accelerators or modules, device-bound identifiers, and whether those capabilities are updateable. A hardware root of trust may support trusted key storage, secure boot, and device authenticity; an immutable root may constrain future updates and ongoing securability. [C13]
• Protocols and services: inventory protocol versions, handshakes, certificates, trust anchors, cipher or signature choices, key establishment, and the data or commands protected. TLS 1.3 uses AEAD algorithms, but application and protocol layers above TLS can still leak information through side channels. [C14]
• Configuration and interfaces: capture cryptographic settings, enabled services, debug or maintenance interfaces, key and certificate locations, provisioning state, and model-specific defaults. Configuration-management practices should be applied to platforms, while unauthorized software installation and execution should be prevented. [C15]
• Source, binaries, and dependencies: use source where available and analyze bytecode or machine code where it is not. Static analysis can examine source, bytecode, or binary code and dependencies; dynamic analysis can identify dependencies loaded at launch time. C16
• Manufacturing and provisioning records: seek records for key generation, installation, injection, replacement, certificates, trust parameters, and test material. Keying-material installation must protect material during entry, and manufacturer-provided test keys must not be used operationally. [C18]
• Vendor and supply-chain documentation: request embedded-cryptography inventories, architecture descriptions, component and dependency lists, signing and key-management information, SBOMs, advisories, and evidence of authenticity. SBOM consumers may need to verify origin and integrity, and binary analysis can identify components missing from an SBOM. C02

For each artifact, preserve provenance: device or model, hardware revision, firmware and bootloader version, build or package identifier, collection date, acquisition method, and any integrity or authenticity evidence. This makes it possible to distinguish a confirmed observation from a vendor assertion, an inference from a binary, or an unresolved hypothesis. The cited evidence emphasizes centralized inventories, discovery outputs, and interchange formats for subsequent risk analysis, but it does not prescribe a single embedded-device record format. C011

A practical discovery sequence

Use a staged sequence that starts with low-impact documentary evidence and proceeds to controlled technical analysis. The sequence below is a planning model derived from the cited evidence; it is not a claim that every device can or should undergo every step. C0118

1. Define the boundary. Include the device, boot and update chain, connected services, development and CI/CD systems, manufacturing and provisioning, vendor components, and the fleet variants relevant to the decision. Identify the sensitive data, critical functions, and expected protection period where known. C01
2. Establish an evidence baseline. Gather architecture documents, product manuals, source repositories, build definitions, binary releases, firmware images, package manifests, SBOMs, vendor declarations, manufacturing records, and configuration baselines. Link every artifact to a product and version. C02
3. Map cryptographic purpose. For every observed call, library, module, certificate, key, protocol, or hardware function, record whether it supports integrity, authentication, identity, key establishment, confidentiality, secure boot, signing, update authorization, or another documented purpose. C06
4. Analyze implementation layers. Search source and build inputs, inspect compiled code and firmware, review boot and package metadata, and examine loaded dependencies in a controlled test environment. Static and dynamic analysis answer different questions and should not be conflated. C16
5. Correlate supply-chain and fleet evidence. Compare SBOMs and vendor declarations with binaries, advisories, build outputs, manufacturing records, and device variants. Look for unlisted components, reused keys or certificates, variant-specific implementations, and differences between intended and deployed configuration. C19
6. Validate selectively. Reproduce findings on representative laboratory hardware or emulation where appropriate, using test keys and non-production data. Record the test conditions and avoid changing production or safety-critical devices merely to confirm an inventory hypothesis. C08
7. Publish an actionable inventory. Include evidence references, confidence, affected versions and variants, protection purpose, dependencies, exposure or criticality, unresolved questions, and the next owner or review point. Correlate with asset, identity, access, endpoint, and configuration inventories where those programs exist. [C02]

Embedded constraints, safety, and testing limits

Embedded discovery often has less observability than conventional host discovery. Proprietary image formats, cross-compiled binaries, vendor SDKs, hardware accelerators, opaque secure elements, stripped symbols, and device-specific build variants can make an algorithm or call difficult to identify. A binary may reveal implementation evidence without revealing the business or safety purpose, while documentation may describe intended behavior without proving what shipped. Treat both as partial evidence and triangulate them. The cited sources explicitly identify limited discoverability for cryptography internal to products and recommend vendor requests; they do not provide a universal technique for proprietary formats or cross-compilation. C0224

Resource constraints also change the collection strategy. A device may have limited storage, processing capacity, maintenance windows, or connectivity, so avoid assuming that an endpoint agent or runtime scan is appropriate. Prefer offline images, build artifacts, vendor records, protocol captures obtained under an approved test plan, and laboratory replicas where they answer the question. If runtime analysis is necessary, define authorization, scope, rollback, data handling, and stop conditions before testing. C0868

Immutable components require explicit treatment. An immutable hardware root of trust may be necessary for a product or customer, yet the same immutability can limit future cryptographic updates. Record which functions are immutable, which are updateable, what trust anchors and signing authorities control updates, and which fleet populations cannot receive a change. Do not infer that a device is crypto-agile merely because its application software can be updated. C135873

What a useful inventory record contains

A discovery record should connect an implementation to its operational meaning. At minimum, capture the product and hardware variant; firmware, bootloader, operating-system, and package versions; component or dependency; algorithm or cryptographic primitive when known; key, certificate, trust-anchor, or module reference; protocol or interface; protection purpose; provisioning and update path; source of evidence; confidence; and limitations. Add fleet scope and criticality when available. This structure supports prioritization because cryptographic discovery is intended to identify where and how cryptography is used and to support replacement planning. C0112

Distinguish observed, declared, inferred, and not yet determined values. For example, a signature algorithm found in a verified package is observed; a vendor list of embedded algorithms is declared; a library attribution inferred from binary patterns is inferred; and an opaque secure element’s internal primitive may remain not yet determined. This distinction prevents a partial scan from being presented as a complete inventory. C02[C19]124

Correlate cryptographic records with asset, identity, credential, access-management, endpoint, and configuration inventories when available. Also identify where cryptography protects sensitive or critical datasets and estimate the period for which protection is needed. These relationships are more useful for migration and risk decisions than a list of algorithm names alone. [C02]2

Lifecycle, identity, and supply-chain dependencies

Discovery must follow cryptographic material through its lifecycle. Keying material can be generated inside a cryptographic module or another system, installed during initial setup, added later, replaced through rekeying or derivation, or distributed during key establishment. Installation records should show who or what performed the operation, how the material was protected, and whether test keys were segregated from operational use. Long-term keys should be inventoried. C187

Device identity deserves a separate inventory relationship. Hardware- or cryptographically bound identifiers, trusted storage, secure boot, and device-authenticity checks can link a physical product to its software and provisioning state. Record the identity issuer or provisioning authority, certificate or key references, trust anchors, rollover and revocation dependencies, and the fleet or manufacturing scope. The evidence supports these categories but does not establish a particular identity architecture for every embedded product. C13[C24]57

Third-party components and build pipelines are part of the discovery boundary. CI/CD workflows can declare third-party dependencies, analyze source, bytecode, or binaries, and generate deployment artifacts; SBOM validation can be strengthened by comparing SBOM data with repositories, advisories, and binary analysis. Record the component version, build provenance, cryptographic use, signing relationship, and whether the deployed artifact matches the reviewed artifact. C17[C20]649

Configuration drift can invalidate an otherwise accurate design inventory. The deployed environment may differ from infrastructure or configuration definitions because of intentional or inadvertent changes, so compare declared configuration with the device or representative deployment after release and periodically where safe. Treat such comparisons as controlled assurance activities, not as permission to modify production devices. C15968

Quality checks and limitations

Before accepting an inventory, check coverage across hardware revisions, firmware branches, boot and recovery paths, update packages, debug states, manufacturing lots, regional or customer variants, and connected services. Confirm that cryptographic findings are linked to evidence rather than copied solely from a generic product description. Ask vendors about internally embedded cryptography and compare their answer with binaries, SBOMs, signing metadata, and observed protocol behavior. C02124

Document uncertainty explicitly. A preliminary draft is not equivalent to a final standard, and the cited evidence includes documents with different statuses and versions, including NIST SP 1800-38B Preliminary Draft, the final Joint Quantum-Readiness Fact Sheet, NIST CSWP 39 Update 1 marked final with an update dated 2026-06-29, and NIST IR 8259 Rev. 1 published 2026-04-20. Preserve the status and version of the evidence used rather than silently treating all passages as interchangeable authority. C01[C22]

Finally, state what the inventory cannot establish. Discovery may locate an algorithm or dependency without proving correct implementation, secure key handling, absence of side channels, or complete fleet coverage. TLS features can support side-channel-resistant implementations, but information leakage can occur in application protocols and applications above TLS. A finding should therefore lead to an appropriately scoped review, test, or remediation decision rather than an unsupported assurance claim. C14[C21]

Conclusion

Embedded-systems discovery is a layered evidence exercise: map the device and lifecycle, collect artifacts and declarations, analyze source and binaries, inspect boot, update, hardware, identity, protocols, configuration, manufacturing, and dependencies, then correlate results across versions and fleet variants. Automated tools are valuable but incomplete, particularly for cryptography internal to products. A defensible inventory records purpose, provenance, affected scope, confidence, and limitations, and uses controlled laboratory validation rather than intrusive experimentation on production or safety-critical devices. C01C0812873