SA-10(4): Trusted Generation

SA-10(4): Trusted Generation requires you to make your developers (including third-party developers) use automated tools to compare each newly generated version of security-relevant hardware descriptions, source code, and object code against the prior version, and to keep proof those comparisons happened. Operationalize it by standardizing diff/compare steps in your build pipeline and contracting for evidence delivery. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Key takeaways:

• You must require comparison tooling for new builds vs previous builds of security-relevant artifacts, not rely on informal reviews. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• “Developer” includes internal teams and third parties building system components or services for you; put the requirement in contracts and SOWs. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Audit readiness depends on repeatable pipeline logs, signed build outputs, and retained comparison reports tied to releases.

The sa-10(4): trusted generation requirement is a supply chain integrity control disguised as a software engineering detail. Examiners care about it because many compromises enter through subtle changes to “security-relevant” code paths (auth, crypto, update mechanisms), build scripts, or firmware descriptions that can be hard to spot after the fact. SA-10(4) forces discipline: every newly generated version must be compared to the prior version using tools, and you must be able to show those comparisons occurred. (NIST SP 800-53 Rev. 5 OSCAL JSON)

For a Compliance Officer, CCO, or GRC lead, the fastest path is to treat SA-10(4) as a release gating requirement: no production release (or delivery acceptance from a third party) without (1) tool-based diffs between versions, (2) review/sign-off on unexpected changes in security-relevant areas, and (3) retained evidence that connects the comparison output to the build/release. You do not need exotic tooling; you need consistent, enforceable process and artifacts that survive staff turnover and audit cycles.

Regulatory text

NIST requirement (verbatim): “Require the developer of the system, system component, or system service to employ tools for comparing newly generated versions of security-relevant hardware descriptions, source code, and object code with previous versions.” (NIST SP 800-53 Rev. 5 OSCAL JSON)

What the operator must do:
You must impose a requirement on the developer (internal engineering or a third party developer) that they use comparison tools each time they generate a new version of security-relevant artifacts, and you must be able to produce evidence that the comparisons occurred and were associated with a specific release/build. The comparisons must cover:

• Security-relevant hardware descriptions (for example, HDL or firmware configuration inputs).
• Security-relevant source code (application code, infrastructure-as-code, scripts).
• Security-relevant object code (compiled binaries, packages, containers, firmware images). (NIST SP 800-53 Rev. 5 OSCAL JSON)

Plain-English interpretation

SA-10(4) means: “Prove that every release changed only what you intended to change.” You do that by automatically comparing the new build to the last known-good build and reviewing diffs in security-relevant areas. This control is less about version control existing, and more about trusted generation: the act of producing build outputs must include tool-based comparison checks that can detect unexpected differences.

Who it applies to

Entity types and contexts commonly in scope

• Federal information systems and programs implementing NIST SP 800-53 controls. (NIST SP 800-53 Rev. 5)
• Contractors and service providers handling federal data, where the system/component/service is developed by the contractor or their subcontractors. (NIST SP 800-53 Rev. 5)

Operational scope

• Internal engineering teams building applications, services, infrastructure modules, agents, firmware, or security tooling.
• Third parties delivering custom code, managed services with delivered components, embedded components, or system integrations where they “generate” build outputs for you.
• CI/CD pipelines, release engineering, and build systems (where comparisons can be automated and logged).

What counts as “security-relevant”

Don’t over-theorize; define it in a way you can run. In practice, teams scope “security-relevant” to the parts of the system that influence confidentiality, integrity, or availability controls, such as:

• Authentication/authorization logic and policy files
• Cryptographic modules, certificates, key-handling logic
• Update mechanisms, package manifests, dependency lockfiles
• Logging/audit pipelines, security telemetry agents
• Infrastructure-as-code that defines network exposure, IAM, secrets, or encryption settings

Write this definition down as a scoping standard and update it when architecture changes.

What you actually need to do (step-by-step)

1) Assign control ownership and decision rights

• Control owner: usually AppSec, DevSecOps, or Release Engineering; GRC owns policy language and evidence expectations.
• Approver for exceptions: CISO/CTO delegate, with documented risk acceptance.
• Third party coverage: Vendor management / procurement ensures contract clauses and evidence delivery obligations.

Deliverable: a one-page control procedure that states who runs comparisons, where results live, and what blocks a release.

2) Define “comparison tooling” for each artifact type

Map tooling to artifact type so engineering can implement without guessing:

• Source code: VCS diffs (Git compare), pull request diffs, and branch protections that require review of changes in flagged paths.
• Object code: binary/package diffs (package manifest compare, SBOM diff, container image layer diff, checksum comparisons) tied to the build job.
• Hardware descriptions/firmware inputs: file diffs plus generated artifact diffs (for example, comparing generated images/checksums).

The requirement is “employ tools for comparing,” so your procedure should name the tools or tool classes and where results are captured. (NIST SP 800-53 Rev. 5 OSCAL JSON)

3) Put the requirement into your SDLC and contracts

For internal teams:

• Add an SDLC control: “Release requires automated comparison output and review notes for security-relevant changes.”
• Add “security-relevant paths” and “release gating criteria” to engineering standards.

For third parties:

• Add contract/SOW language requiring tool-based comparisons for each release/delivery and requiring delivery of comparison evidence with the artifact.
• Require traceability: the evidence must reference version identifiers (commit hash, build ID, artifact digest).

Daydream tip (earned, not forced): Daydream is useful here as a control registry and evidence tracker, because SA-10(4) often fails on “we do it, but can’t prove it.” Create a SA-10(4) control record with owner, procedure, and recurring evidence tasks so you can request the same artifact bundle every release cycle.

4) Implement release gates and review workflow

Minimum viable gating pattern:

• CI job generates comparisons for security-relevant source and build outputs versus previous release baseline.
• Pipeline stores results (diff report, artifact digests, SBOM diff if you generate SBOMs).
• Reviewer signs off in the change record or pull request when diffs include security-relevant areas.

Focus on two outcomes:

1. Detection: unexpected changes are surfaced.
2. Accountability: someone reviews and records disposition.

5) Establish a baseline and “previous version” reference

SA-10(4) explicitly requires comparison to “previous versions.” (NIST SP 800-53 Rev. 5 OSCAL JSON) Define what “previous” means operationally:

• Prior production release
• Prior approved delivery from third party
• Prior “golden” build for that branch/product line

Document how the pipeline retrieves the baseline artifact and validates it (for example, by digest match to your artifact repository).

6) Evidence retention and audit packaging

Make evidence retrieval a product requirement for your toolchain:

• Store diff reports and build logs in an immutable or access-controlled repository.
• Ensure evidence is searchable by release/version.
• Retain evidence long enough to cover your assessment window and internal investigation needs (set your retention based on your program requirements).

Required evidence and artifacts to retain

Keep artifacts that show comparison happened, what was compared, and who approved:

Core evidence (expected in most audits)

• SA-10(4) procedure (control narrative) mapping: scope, tools, gating, approvals.
• CI/CD logs showing comparison step execution (job IDs, timestamps, status).
• Diff outputs for security-relevant source changes (PR links, commit compare).
• Artifact comparison outputs:
  • checksums/digests for previous vs new object code
  • package manifest/lockfile diffs
  • container image diff summaries (layers, packages)
• Change/release record tying approval to the comparison outputs.

Third party-specific evidence

• Contract/SOW clause requiring tool-based comparisons and evidence delivery. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• Delivered comparison report bundle per release, with version identifiers.
• Acceptance checklist showing you verified the bundle before deployment/use.

Common exam/audit questions and hangups

Auditors tend to press on four points:

1. “Show me the tool output.” Screenshots are weak. Provide system-generated logs/reports tied to release IDs.
2. “What is security-relevant in your environment?” If you can’t define it, you can’t prove coverage.
3. “Do third parties follow the same rule?” The control says “require the developer,” so outsourced development must be contractually bound. (NIST SP 800-53 Rev. 5 OSCAL JSON)
4. “How do you compare object code?” Many teams only diff source. You need evidence for compiled outputs too (hashes, package diffs, image diffs).

Frequent implementation mistakes (and how to avoid them)

Mistake	Why it fails SA-10(4)	Fix
Relying on peer review alone	Review is not “tools for comparing newly generated versions”	Add automated compare jobs and retain outputs. (NIST SP 800-53 Rev. 5 OSCAL JSON)
Only comparing source code	SA-10(4) also covers object code and hardware descriptions	Add artifact-level comparisons (digests, package diffs) to build pipeline. (NIST SP 800-53 Rev. 5 OSCAL JSON)
No defined “previous version”	Teams compare against arbitrary commits	Define baseline selection rules per product/repo and document them.
Third party delivers binaries without proof	You cannot show you “required” comparison tooling	Add SOW clause + acceptance criteria requiring comparison evidence. (NIST SP 800-53 Rev. 5 OSCAL JSON)
Evidence exists but isn’t retrievable	Audit failure becomes an evidence management failure	Centralize evidence, index by release, and test retrieval quarterly.

Enforcement context and risk implications

No public enforcement cases were provided in the source catalog for this requirement, so this page does not list cases.

Operationally, SA-10(4) reduces risk from:

• Malicious or accidental insertion of security-impacting changes
• Build pipeline tampering that alters object code without obvious source diffs
• Third party deliveries where you lack transparency into what changed

Treat gaps as a supply chain integrity issue: if you can’t compare versions reliably, you are slower to detect compromise and slower to scope impact.

A practical 30/60/90-day execution plan

First 30 days (stabilize scope and accountability)

• Name a control owner and backups; document decision rights for exceptions.
• Publish a “security-relevant artifact” scoping standard and get engineering sign-off.
• Inventory systems/components/services where you generate releases or accept third party deliveries.
• Draft contract/SOW language for third party developers requiring comparison tooling and evidence delivery. (NIST SP 800-53 Rev. 5 OSCAL JSON)
• In Daydream (or your GRC system), create the control record: owner, procedure, and an evidence checklist aligned to releases.

By 60 days (implement minimum viable gates)

• Implement CI comparison steps for source code and at least one object-code comparison method per build type (digest comparisons plus package/container diffs where applicable).
• Add release checklist items: “comparison evidence attached” and “security-relevant diffs reviewed.”
• Start collecting evidence bundles per release in a centralized repository; test retrieval end-to-end.
• Roll out updated third party delivery acceptance checklist requiring comparison evidence before you deploy.

By 90 days (expand coverage and make it repeatable)

• Extend comparisons to remaining artifact types (including hardware descriptions/firmware inputs if in scope).
• Add automated alerts for unexpected changes in security-relevant paths.
• Train release managers and approvers on what “good evidence” looks like and how to reject incomplete bundles.
• Run an internal mock audit: pick a recent release and produce the full evidence package within the same business day.

Frequently Asked Questions

Do we need special tools beyond Git to meet SA-10(4)?

Not always. Git diffs can cover source, but you still need comparison tooling for object code and any hardware descriptions in scope. The key is tool-based comparison with retained outputs tied to the release. (NIST SP 800-53 Rev. 5 OSCAL JSON)

What if our third party only delivers a compiled binary?

Require them, contractually, to provide comparison evidence against the prior delivered version and include identifiers that let you tie evidence to the binary you received. Without that, you cannot show you “required the developer” to perform trusted generation comparisons. (NIST SP 800-53 Rev. 5 OSCAL JSON)

How do we define “previous version” for hotfixes and emergency patches?

Define “previous” as the last approved production release for that product line, then compare the hotfix build outputs against that baseline. Document the baseline selection rule and keep it consistent.

Does SA-10(4) require a human to review every diff?

SA-10(4) requires tools for comparing versions; it does not, by itself, specify human review. In practice, you should require review and sign-off when diffs touch security-relevant areas so you can explain how comparisons affect release decisions. (NIST SP 800-53 Rev. 5 OSCAL JSON)

Are SBOM diffs required for SA-10(4)?

The text does not mandate SBOMs. If you already generate SBOMs, diffing them is a strong way to show object-code and dependency changes between builds, and it fits the “compare newly generated versions” intent. (NIST SP 800-53 Rev. 5 OSCAL JSON)

What’s the fastest way to get audit-ready evidence for this control?

Make the comparison step part of CI/CD and store outputs automatically with the build ID and artifact digest. Then track the recurring evidence bundle in a system like Daydream so you can produce the same package for any sampled release.