CoinJoin improves privacy by allowing multiple users to construct a single collaborative Bitcoin transaction. It combines transaction inputs (UTXOs) from multiple participants into a single Bitcoin transaction, making it more difficult for an observer to determine which participant controls each resulting output. The architecture consists of four main components: participants, inputs, outputs, and a coordination mechanism. Privacy can also be weakened when users later spend several CoinJoin outputs together or combine them with previously identified coins, reconnecting transaction histories that CoinJoin had helped separate. Can a CoinJoin coordinator steal users’ Bitcoin?