Understanding Zero-Knowledge Proofs Through the Source Code of Tornado Cash

Based on <a href="https://en.wikipedia.org/wiki/Zero-knowledge_proof" rel="noopener ugc nofollow" target="_blank">Wikipedia</a>, the definition of the Zero Knowledge Proof (ZKP) is the following: <blockquote> … zero-knowledge proof or zero-knowledge protocol is a method by which one party (the prover) can prove to another party (the verifier) that a given statement is true while the prover avoids conveying any additional information apart from the fact that the statement is indeed true. The essence of zero-knowledge proofs is that it is trivial to prove that one possesses knowledge of certain information by simply revealing it; the challenge is to prove such possession without revealing the information itself or any additional information. </blockquote> The technology of ZKP can be widely used in many different fields like anonymous voting or anonymous money transfer that are difficult to solve on a public database like the blockchain. <a href="https://tornado.cash/" rel="noopener ugc nofollow" target="_blank">Tornado Cash</a> is a coin mixer that you can use to anonymize your Ethereum transactions. Because of the logic of the blockchain, every transaction is public. If you have some ETH on your account, you cannot transfer it anonymously, because anybody can follow your transaction history on the blockchain. Coin mixers, like Tornado Cash, can solve this privacy problem by breaking the on-chain link between the source and the destination address by using ZKP. If you want to anonymize one of your transactions, you have to deposit a small amount of ETH (or ERC20 token) on the Tornado Cash contract (ex.: 1 ETH). After a little while, you can withdraw this 1 ETH with a different account. The trick is that nobody can create a link between the depositor account and the withdrawal account. If hundreds of accounts deposit 1 ETH on one side and the other hundreds of accounts withdraw 1 ETH on the other side, then nobody will be able to follow the path where the money moves. The technical challenge is that smart contract transactions are also public like any other transaction on the Ethereum network. This is the point where ZKP will be relevant. <a href="https://betterprogramming.pub/understanding-zero-knowledge-proofs-through-the-source-code-of-tornado-cash-41d335c5475f">Click Here</a>