Tornado Cash is a fully decentralized non-custodial protocol allowing private transactions in the crypto-space. As a decentralized protocol, Tornado.Cash smart contracts have been implemented within the Ethereum blockchain, making them immutable. They can neither be changed nor tampered with. 

Therefore, nobody - including the original developers - can modify or shut them down. All governance and mining smart contracts are deployed by the community in a decentralized manner.

As a non-custodial protocol, users keep custody of their cryptocurrencies while operating Tornado.Cash. This means that at each deposit, they are provided with the private key enabling the access to the deposited funds, which gives users complete control over their assets.