Solva is a zero-knowledge Proof of Solvency protocol on Stellar. A custodial
institution proves that its reserves are greater than or equal to its
liabilities, without revealing any individual customer balance.

## Why both sides of the balance sheet [#why-both-sides-of-the-balance-sheet]

Proving that you hold assets is not the same as proving you are solvent. Most
published proof of reserves systems attest only the asset side. Solva binds both
sides in one proof, so a healthy reserve figure cannot hide a larger liability.

```
Proof of Solvency = Proof of Reserves + Proof of Liabilities
```

## How a proof cycle works [#how-a-proof-cycle-works]

1. The orchestrator fetches signed reserve balances from each source and
   verifies the ECDSA signatures.
2. It loads the customer liabilities for the tenant.
3. It sends reserves, liabilities, and the previous reserve total to the prover.
4. The prover builds the Poseidon2 Merkle Sum Tree, generates the
   Noir/UltraHonk proof, and returns the proof, the public inputs, and the tree.
5. The orchestrator publishes the proof to the Soroban proof-registry contract,
   which verifies it on-chain and stores the root and totals.
6. The proof and tree are persisted to an append-only audit log.

The public sees only the totals and the commitment root. Customers can check
that their own balance is included in the committed tree.