Component behavior in FIPS mode

When FIPS mode is enabled, Sigstore components restrict cryptographic operations and supported features to FIPS-approved algorithms and cryptographic modules. The following sections describe the behavior and limitations for each component.

Fulcio
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Client signing requests are restricted to FIPS-approved algorithms only. Requests that use non-approved algorithms are rejected.

Rekor
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The following features are disabled in FIPS mode.

Table 1. Disabled Rekor features
Feature Reason

Helm, RPM entry types

Depend on PGP, which is not FIPS-approved

Alpine entry type

Uses SHA-1 for signature verification

PGP, SSH, Minisign signature formats

Use unvalidated crypto modules

Client signing requests are restricted to FIPS-approved algorithms only.

The Rekor CLI defaults to x509 format instead of pgp when FIPS mode is active.

Cosign
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  • Password-protected cosign keys cannot be created or loaded. In FIPS mode, cosign generates unencrypted keys instead.
  • Storing secrets to GitHub Actions is not available.
  • Azure KMS with certificate-based authentication is not available.

Gitsign
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Only SHA-2 and SHA-3 hash algorithms are accepted for commit signatures and timestamps.

Timestamp Authority (TSA)
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Sigstore-encrypted and cosign-encrypted private key formats are not supported.