To secure your software supply chain, you should consider signing your container images with attestations. Runtime environments like Kubernetes Engine can validate the signature and run only the container images that you have signed/attested with Binary Auth.
You need to create an Attestor, which is associated with the metadata of the an asymetric key pair that's used to sign and validate a signature for an image digest.
Create a Note
A is a metadata entry in Google Container Analysis and is required when associating with an Attestor. An Attestation ultimately becomes an instance of a Note.
You need to create a key pair so that you can sign an attestation with a private key, and later, verify it with a public key. You can create your own key pair, but this guide will use Cloud KMS.
Enable API
gcloud services enable cloudkms.googleapis.com
Create a Keyring
gcloud kms keyrings create attestor-keyring --location global
You can create an attestation for a container image, but you'll need the full SHA256 container image digest. The easiest way to find this is from Container Registry:
Once the container image has a signed attestation, it can then be used to authorize deployments into a Kubernetes Engine cluster by enabling Binary Authorization.
