The message didn't reveal the nature of the "secrets," but the hackers made available on the site a multi-part encrypted file that was said to contain them. It's impossible to determine what's actually in the files, which were named for judges on the U.S. Supreme Court.
The message went on to demand a number of reforms to the U.S. legal system.
Martyn Williams covers mobile telecoms, Silicon Valley and general technology breaking news for The IDG News Service. Follow Martyn on Twitter at @martyn_williams. Martyn's e-mail address is email@example.com