Q21

How do you sign build artifacts or container images within a GitHub Actions run to verify their authenticity?

Q: How do you sign build artifacts or container images within a GitHub Actions run to verify their authenticity?

> Use **Cosign** (from Sigstore) to sign container images using GitHub's OIDC identity: 1. Authenticate to AWS/GCP using OIDC to fetch short-lived registry credentials. 2. Build and push the Docker image to your container registry. 3. Install Cosign in the runner workflow. 4. Run `cosign sign --yes ` utilizing keyless signing. Cosign validates the runner's OIDC JWT identity and records the signature in the Sigstore transparency log (Rekor).

💬Answer

Use Cosign (from Sigstore) to sign container images using GitHub's OIDC identity:

Authenticate to AWS/GCP using OIDC to fetch short-lived registry credentials.
Build and push the Docker image to your container registry.
Install Cosign in the runner workflow.
Run cosign sign --yes <image-digest> utilizing keyless signing. Cosign validates the runner's OIDC JWT identity and records the signature in the Sigstore transparency log (Rekor).

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Apurv Gujjar

DevOps & Cloud Engineer

Specialized in:DevOpsAWSGCPKubernetesTerraformDocker

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