Verifying signed artifacts

Every release signs its customer-facing artifacts so you can prove they came from us and haven’t been tampered with — including in an air-gapped install.

There are two kinds of artifact:

1. Core container images — query-api, ingest-gateway, enrollment, aggregator, lifecycle-manager, portal-ui, and sensor — published to ghcr.io/ultrvlt/<name>.
2. The Helm umbrella chart — an OCI artifact at ghcr.io/ultrvlt/charts/ultrvlt.

What each release produces

Artifact	Signature	Extra
Each core image	cosign key-based signature	CycloneDX SBOM + SLSA provenance attestation
Helm chart (OCI)	cosign key-based signature	SLSA provenance attestation

• Key-based, not keyless. Verification needs only the published public key — no Fulcio/Rekor, no network. This is a direct consequence of the offline-first invariant. Signatures are made with --tlog-upload=false, so they live in the OCI registry alongside the artifact rather than in a public transparency log.
• SBOM (CycloneDX) is attached as a cosign attestation, offline-verifiable with the same key.
• SLSA build provenance is also a cosign key-based attestation (--type slsaprovenance), offline-verifiable with the same key.
• cosign version: releases are signed with cosign v2. Verify with any cosign ≥ v2 (v3 reworked --tlog-upload and would break the offline flow).

Verifying an install

Fetch the public key once, then verify offline:

export ULTRVLT_VERSION=0.1.25   # the version you're installing
curl -fsSLO https://raw.githubusercontent.com/ultrvlt/ultrvlt/main/deploy/cosign/cosign.pub

# Verify every core image you're about to run.
for img in query-api ingest-gateway enrollment aggregator lifecycle-manager portal-ui sensor; do
  cosign verify --key cosign.pub --insecure-ignore-tlog=true \
    ghcr.io/ultrvlt/$img:$ULTRVLT_VERSION
done

# Inspect an image's SBOM.
cosign verify-attestation --key cosign.pub --insecure-ignore-tlog=true \
  --type cyclonedx ghcr.io/ultrvlt/query-api:$ULTRVLT_VERSION \
  | jq -r '.payload | @base64d | fromjson | .predicate' > query-api.sbom.json

# Verify build provenance (offline, same key).
cosign verify-attestation --key cosign.pub --insecure-ignore-tlog=true \
  --type slsaprovenance ghcr.io/ultrvlt/query-api:$ULTRVLT_VERSION

# Verify the chart before installing.
cosign verify --key cosign.pub --insecure-ignore-tlog=true \
  ghcr.io/ultrvlt/charts/ultrvlt:$ULTRVLT_VERSION
helm install ultrvlt oci://ghcr.io/ultrvlt/charts/ultrvlt --version $ULTRVLT_VERSION

Note

--insecure-ignore-tlog=true is expected: signatures and attestations are registry-local (not in the transparency log), which is what makes offline verification possible.

Release channels

On top of the per-version artifacts, each release publishes a channel pointer — a small cosign-signed OCI artifact at ghcr.io/ultrvlt/charts/ultrvlt-channels:<channel> that names the chart version and digest a channel currently points at, plus the upgrade metadata the lifecycle manager consumes.

• latest moves on every release.
• stable (the hands-off default) is promoted out-of-band from an already-released version.

Both are signed and verified with the same offline key, so channel resolution works air-gapped:

cosign verify --key cosign.pub --insecure-ignore-tlog=true \
  ghcr.io/ultrvlt/charts/ultrvlt-channels:stable