Verify Signed Kubernetes Artifacts [page]deterministic

##

You will need to have the following tools installed:

• `cosign` ([install guide](https://docs.sigstore.dev/cosign/system_config/installation/))
• `curl` (often provided by your operating system)
• `jq` ([download jq](https://jqlang.github.io/jq/download/))

## Verifying binary signatures

The Kubernetes release process signs all binary artifacts (tarballs, SPDX files, standalone binaries) by using cosign's keyless signing. To verify a particular binary, retrieve it together with its signature and certificate:

```bash URL=https://dl.k8s.io/release/v/bin/linux/amd64 BINARY=kubectl

FILES=( "$BINARY" "$BINARY.sig" "$BINARY.cert" )

for FILE in "${FILES[@]}"; do curl -sSfL --retry 3 --retry-delay 3 "$URL/$FILE" -o "$FILE" done ```

Then verify the blob by using `cosign verify-blob`:

```shell cosign verify-blob "$BINARY" \ --signature "$BINARY".sig \ --certificate "$BINARY".cert \ --certificate-identity krel-staging@k8s-releng-prod.iam.gserviceaccount.com \ --certificate-oidc-issuer https://accounts.google.com ```

> Note: Cosign 2.0 requires the `--certificate-identity` and `--certificate-oidc-issuer` options.

To learn more about keyless signing, please refer to [Keyless Signatures](https://docs.sigstore.dev/cosign/signing/overview/).

Previous versions of Cosign required that you set `COSIGN_EXPERIMENTAL=1`.

For additional information, please refer to the [sigstore Blog](https://blog.sigstore.dev/cosign-2-0-released/)

## Verifying image signatures

For a complete list of images that are signed please refer to [Releases](/releases/download/).

Pick one image from this list and verify its signature using the `cosign verify` command:

```shell cosign verify registry.k8s.io/kube-apiserver-amd64:v \ --certificate-identity krel-trust@k8s-releng-prod.iam.gserviceaccount.com \ --certificate-oidc-issuer https://accounts.google.com \ | jq . ```

### Verifying images for all control plane components

To verify all signed control plane images for the latest stable version (v), please run the following commands:

```shell curl -Ls "https://sbom.k8s.io/$(curl -Ls https://dl.k8s.io/release/stable.txt)/release" \ | grep "SPDXID: SPDXRef-Package-registry.k8s.io" \ | grep -v sha256 | cut -d- -f3- | sed 's/-/\//' | sed 's/-v1/:v1/' \ | sort > images.txt input=images.txt while IFS= read -r image do cosign verify "$image" \ --certificate-identity krel-trust@k8s-releng-prod.iam.gserviceaccount.com \ --certificate-oidc-issuer https://accounts.google.com \ | jq . done < "$input" ```

Once you have verified an image, you can specify the image by its digest in your Pod manifests as per this example:

```console registry-url/image-name@sha256:45b23dee08af5e43a7fea6c4cf9c25ccf269ee113168c19722f87876677c5cb2 ```

For more information, please refer to the [Image Pull Policy](/docs/concepts/containers/images/#image-pull-policy) section.

## Verifying Image Signatures with Admission Controller

For non-control plane images (for example [conformance image](https://github.com/kubernetes/kubernetes/blob/master/test/conformance/image/README.md)), signatures can also be verified at deploy time using [sigstore policy-controller](https://docs.sigstore.dev/policy-controller/overview) admission controller.

Here are some helpful resources to get started with `policy-controller`:

• [Installation](https://github.com/sigstore/helm-charts/tree/main/charts/policy-controller)
• [Configuration Options](https://github.com/sigstore/policy-controller/tree/main/config)

## Verify the Software Bill Of Materials

You can verify the Kubernetes Software Bill of Materials (SBOM) by using the sigstore certificate and signature, or the corresponding SHA files:

```shell # Retrieve the latest available Kubernetes release version VERSION=$(curl -Ls https://dl.k8s.io/release/stable.txt)

# Verify the SHA512 sum curl -Ls "https://sbom.k8s.io/$VERSION/release" -o "$VERSION.spdx" echo "$(curl -Ls "https://sbom.k8s.io/$VERS …(trimmed)