Use Rekor as an immutable transparency log for signing records, and query it during verification to confirm that a signature was published and not silently replaced. Protect access to submission workflows, monitor for unexpected entries, and keep the log reference in your build and deployment checks. Treat missing log evidence as a policy failure, not a warning to ignore.
Why Rekor matters in a signing workflow
Rekor is most useful when you treat it as a source of verification evidence, not as a logging add-on. Its job is to give you an immutable record that a signing event occurred, so your build and release checks can confirm the signature was published and has not been quietly swapped later. That changes Rekor from “nice to have” to part of the trust decision.
The practical implication is that Rekor only adds value when verification actually queries it. If you sign artifacts but never check the transparency log during CI, CD, or admission control, you are relying on a claim rather than an auditable record. In software supply chain terms, the log is strongest when it is consulted at the point where the artifact is promoted or consumed, not after the fact.
For teams that want the broader operating model around provenance, signing, and release integrity, the Software Supply Chain Security Guide is the most direct companion resource because Rekor sits inside that larger integrity and trust chain.
How to use Rekor without weakening the trust chain
Rekor best practices start with tight control over who can submit entries and how those submissions are generated. The submission path should be protected as a privileged workflow, because if an attacker can inject bogus records or influence what gets logged, the transparency property becomes less useful even if the log itself remains append-only. Protect the log reference just as carefully as the signature artifact reference.
Verification should be deterministic and routine. Query Rekor as part of your normal build, deploy, or promotion checks, and fail closed when the expected log evidence is missing. The absence of a valid transparency record should be treated as a release integrity problem, not as a harmless exception to investigate later.
Operationally, monitoring matters because the log can reveal unexpected publication patterns, duplicated submissions, or entries that do not match the expected pipeline behaviour. That is why Rekor works best when paired with alerting, review of anomalous log activity, and a clear rule for what counts as acceptable evidence for a given artifact or release.
Where teams usually get Rekor wrong
The common mistake is to treat Rekor as an archive rather than an enforcement point. If the log is only inspected manually, or only after something looks suspicious, it does not materially strengthen release confidence. Another frequent failure is to protect the signing key but ignore the workflow that publishes or references the log entry, which leaves a gap between “signed” and “provable.”
Teams also underestimate how much trust depends on the surrounding metadata. If build systems, deployment gates, or release manifests point to the wrong Rekor entry, or if that reference can be altered without detection, the transparency check is no longer meaningful. The log itself may still be intact, but the trust path to it has been weakened.
Risk and Threat Considerations
Rekor reduces ambiguity in the release process, but it does not remove the need to protect the submission path and the verification path. If an attacker can suppress a log reference, substitute an entry, or cause teams to ignore missing evidence, they can create a false sense of integrity even when the artifact chain has been compromised.
Failure mechanism: Weak controls around submission, reference handling, or verification allow a signed artifact to appear legitimate without a trustworthy transparency record, or allow malicious entries to blend into normal pipeline activity.
Impact: Release integrity checks become unreliable, compromised artifacts are harder to distinguish from valid ones, and responders lose a clear audit trail for proving what was actually signed and published.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
SLSA, CIS Controls v8 and NIST SP 800-53 Rev 5 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| SLSA | Build Provenance | Rekor is used to verify artifact provenance and signing evidence in the release chain. |
| Recommendation — Verify build provenance and block promotion when the transparency record is missing or inconsistent. | ||
| CIS Controls v8 | CIS-16 — Application Software Security | Rekor best practices protect release integrity and trusted software delivery workflows. |
| Recommendation — Enforce integrity checks for release artifacts and deployment gates. | ||
| NIST SP 800-53 Rev 5 | SI-7 — Software, Firmware, and Information Integrity | Transparency-log verification supports integrity checks for signed software and release records. |
| AU-10 — Non-Repudiation | Rekor provides auditable evidence that signing records were published and retained. | |
| AC-6 — Least Privilege | Submission workflows for transparency logs should be tightly restricted to reduce abuse risk. | |
| Recommendation — Require integrity validation before accepting or deploying signed artifacts. Retain verifiable evidence that signing events were recorded and reviewable. Limit log submission and publishing permissions to the minimum required set. | ||
Practitioner Guidance
What to verify: Make sure every protected release path has an automated Rekor query, and that the pipeline fails when the expected entry, inclusion evidence, or matching signature record is absent. If the check is optional, the transparency log is not really part of the control.
What to prioritise: Protect the workflow that creates and publishes entries before you polish dashboards or manual review processes. The highest-value control is consistent, machine-enforced verification at promotion time, because that is where silent substitution is most damaging.
Practitioner takeaway: Rekor is only effective when the organisation treats missing or mismatched log evidence as a trust failure that blocks release, not as a documentation issue to reconcile later.