OpenChallSpec - The Open Challenge Specification

The OpenChallSpec (OCS) is a specification for jeopardy style Capture The Flag competition challenges. It defines a challenge.yml file which is used to describe the metadata and deployment of any CTF challenge. Usually, organizers either tediously enter metadata into their CTF platform and deploy challenges manually, or create their own challenge format that automates some or all of this work, but only covers their specific use case. The OCS aims to solve this by providing a challenge format that covers all use cases and works seamlessly with any CTF platform or tool.

The OCS has a few distinct design goals:

• Cover everyone’s use cases. If a CTF platform or deployment tool has support for a certain feature, you should be able to configure this feature inside challenge.yml (within reason).
• Intercompatibility with every CTF platform and tool. A challenge written using the OCS for a CTF running CTFd should also work with any other CTF platform and be painless to import, granted that some features not shared between the platforms may not work.
• Challenge packageability. A folder containing a challenge should be able to be zipped, committed to a git repository, etc. and sent to another person while retaining all functionality, even if the challenge author and receiving person don’t use the same tools or have the same environment.

If you have a use case the OCS doesn’t cover, or a feature in your CTF platform not configurable from the OCS, don’t hesitate to submit an issue so that it can be added to the spec.