Proof-of-liabilities root (Merkle sum tree)

Solvency without disclosure. We publish a Merkle sum-tree ROOT and the TOTAL of all netting liabilities; each account can request an inclusion proof showing their balance is inside that total, and the total is checkable against on-chain backing. Nobody learns anybody else's balance. This proves inclusion and the total — it cannot alone prove no account was omitted; that assurance comes from many users each checking their own proof.