Sign a Helm chart by adding the sign option to helm package, which writes a provenance file next to the archive. Verify with helm verify, or add the verify option to helm install so a bad chart stops before it renders. It proves integrity and signer key, not that the chart is safe.
Sign
Packaging with a key and keyring produces both the chart archive and a file ending in .prov:
helm package --sign --key 'John Smith' --keyring path/to/keyring.secret mychart
The key value must match part of the key's user id, such as a name or email, because the fingerprint does not work. The signing key must be in a keyring file, and users of GnuPG 2.1 or later may need to export their private key into that format first. Upload both the archive and the .prov file to the chart repository.
What the provenance file contains
| Content | Why it matters |
|---|---|
| A copy of Chart.yaml | Easy inspection |
| A SHA-256 digest of the chart archive | Detects tampering |
| A PGP signature over the file | Shows which key signed |
Verify
helm verify mychart-0.1.0.tgz
helm install --generate-name --verify mychart-0.1.0.tgz
If the public key is not in the default keyring location, add a keyring path. A mismatch reports that the sha256 sum does not match. A missing or corrupt .prov file, a missing key or a bad signature are also failures, and the Helm docs say any failure is a reason to distrust the package.
What it proves and what it leaves out
Helm provenance proves the archive matches the digest recorded at packaging time, and the PGP signature shows which key signed it. That second point only means something if you trust the public key. Helm does not act as a certificate authority, so deciding which keys to trust is your job.
It does not tell you what the templates do, whether the images they reference are signed, or whether any dependency is vulnerable.
A rollout checklist
- Choose a dedicated signing key and keep the private half off developer laptops where possible.
- Publish the public key through a channel consumers already trust.
- Make verify mandatory in the pipeline that installs charts.
- Pin the images inside the chart by digest and verify those separately.
- Plan key rotation and record who can sign.
The source page notes it had not yet been updated for Helm 4, so check current docs for your version before you roll this out.
Where Safeguard fits
Safeguard can scan container images and manifests for vulnerabilities, and policy gates can enforce rules on what ships. Try the free scan.
Quick check
Does helm verify check the container images in the chart?
No. It checks the chart archive against its provenance file only. Images need their own signing and verification.
Can I use keyless signing with Helm provenance?
The Helm documentation describes PGP based signing. Check current Helm docs for other options before assuming support.
Sources
Last reviewed: 19 October 2026.
