"Why isn't this a smart contract?"
Because it would make it less private.
Every DeFi protocol that runs on a smart contract publishes its entire state on-chain. Every deposit, every withdrawal, every position — queryable by anyone. Chainalysis doesn't need to hack you. They just read the event logs.
Our lending protocol uses a centralised backend wallet. Every user's deposit lands in the same wallet. Funds go to Aave V3. Withdrawals come from the shared pool.
An on-chain observer sees transfers in and transfers out of one address. That's it. No events mapping depositors to withdrawers. No position tracking on a public ledger.
The privacy isn't bolted on. It's a consequence of the architecture.
"But what about trustlessness?"
Valid concern. Here's the roadmap:
1. Today: Custodial architecture, structural privacy, optional ZK shielding via Railgun
2. Next: Shielded smart contract using Railgun's composable vault infrastructure (when it matures)
3. Long term: Fully trustless shielded vault — no custodian, no database, ZK everything