Yes that's correct, they're basically a large multi-sig solution which distributes incoming Bitcoin private keys over a network of darknodes via multi-party-computation, you need to stake 100k REN to run a darknode and get paid fees from volume of transactions for keeping it running, it's a pretty neat concept and as far as I understand they're the only such solution that's live at the moment, similar solution (not live) would be tBTC and I am sure they'll be more in the future.