Comet

Comet is a private lending protocol on Aztec where users deposit collateral and borrow assets, with deposit size, debt and liquidation activity hidden from outside view. It targets holders who do not want to publish their balance sheet but need leverage or liquidity.

Mechanically, each market keeps its own interest rate curve, with borrow rates rising as utilization increases. Positions are recorded as encrypted notes in Aztec's private state: balance changes consume old notes and create new ones, while public state stores only nullifiers to prevent double spending. Contracts are written in Noir, and borrowing or repaying generates a client-side zero-knowledge proof showing the collateral ratio stays above the floor and the notes are unspent. Liquidations are submitted as proofs too, so a liquidator can show a position is below threshold without revealing its size.