The US Treasury prints the money, and hands it to the Fed who lends it back to us at interest. The Fed is a group of Int'l bankers and royal families like Rothschild and Rockefeller.
The creature from Jeckel Island is the best book about the founding of the Fed.
The cash is not secured in any way. We print the money and pay interest on it.
I know you know this Mike but it is always helpful to spread the news.