Here's what you can do:

1. Clone the repository. Make an insignificant change to the initial commit in order to change all commit hashes. Push to github as a new repository.

2. Create a password "protected" zip file (or smaller volumes) containing the repository. Use a password that's easily found in common wordlists. Commit it to another project and push to github.

Microsoft GitHub may be centralized, but it's not omniscient. RIAA may be a control freak, but it's not omnipotent. Let information be free for all.