Each Trustless Bitcoin Vault is a Bitcoin-native UTXO controlled by programmatic conditions. When BTC is deposited, the vault locks funds under a custom Bitcoin Script that enforces withdrawal rules through cryptographic proofs, not trust. The system uses garbled circuits to verify off-chain zero-knowledge (ZK) proofs attesting to events on external chains, such as repayments, liquidations, or ownership claims. These verified proofs then update the vault’s state directly on Bitcoin, allowing it to interact with DeFi protocols (like lending markets or stablecoin issuers) without requiring bridges or wrapped assets. In other words, vaults don’t move BTC between chains, they extend its logic. Bitcoin remains on Bitcoin, but its state becomes verifiable everywhere.