To use DRM you have to own the content, and you have to disclose the DRM protections in advance. Contract development is usually covered as work for hire in the

To use DRM you have to own the content, and you have to disclose the DRM protections in advance. Contract development is usually covered as work for hire in the US, and the client paying for the work owns it by default. I'd be surprised if the client agreed in advance to the contractor owning the content, or to DRM.