Docker Notary is an OSS tool that enables signing of assets such as images, files and containers. This means that the provenance of assets can be asserted which is superuseful in regulated environments and better practice everywhere. As an example, when a container is created, it's signed by a private key and a hash, tied to the publisher's identity, stored as metadata. Once published, the provenance of the container (or other asset) can be checked using the image hash and the publisher's public key. There are publicly available, trusted registries such as the Docker Trusted Registry, but it's also possible to run your own. Our teams have reported some spiky edges running local Notary servers and suggest using a registry that includes Notary where possible.