Hush Hush is a privacy extension to Aave interest bearing tokens that let anyone deposit into a "anonymous savings account" that hides links between deposits and withdrawals. This means that anyone can see who deposits into the "pool" but that it is hidden whoever is withdrawing. We support fixed size deposits and variable withdraws, meaning that we have multiple pools, e.g., one pool for 1000$, one for 10000$ deposits etc, but you can withdraw any fraction of your balance when you choose to.
How It's Made
Hush Hush uses Aave Interest Bearing tokens (aTokens) together with zero-knowledge proofs to support the anonymous savings account. More precisely we will be using ZK-SNArKs to prove the validity of state updates for both deposit and withdrawal into the pool. We are building on the basis of Tornadocash and semaphore to construct the circuits for the proof. The circuits are themselves written in Circom by Iden3, and proof generation is done in WASM for increased performance