Policies Polyglot: Evaluating Custom Predicates

Posted on March 20, 2024

Attestations are a wonderful way to attach metadata to container images in a secure manner. One of the most popular formats is SLSA Provenance which is used to provide information on how the image was created. Our Hitchhiker’s Guide demonstrates how to write policies to assert the contents of the SLSA Provenance. Here, we expand on that approach to assert the contents of any attestation format, even completely made up ones.