What Is Tornado Cash? Why Do Hackers Still Use It?
Why Does Tornado Cash Matter to Crypto Users?
Tornado Cash is a crypto mixing protocol built to make Ethereum transactions harder to follow. It keeps appearing in stories about stolen funds, blockchain tracing and financial privacy.
Public blockchains record every transfer, so some users want that exposure reduced. Criminals do too, for different reasons.
This guide explains how Tornado Cash works, why hackers still use it, and where the legal fight stands. Not every user has bad intent. Many don't.
What Is Tornado Cash and How Does It Work?
Tornado Cash is a set of open-source smart contracts that went live on Ethereum in 2019. A smart contract is code that runs on a blockchain and follows fixed rules.
That's the big difference from a normal wallet or exchange. A wallet stores your keys. An exchange holds your coins and knows who you are. It does neither. It's a pool that accepts deposits and releases withdrawals.
The Purpose of Crypto Mixing and Transaction Privacy
Ethereum is transparent by default. Anyone can paste your address into a block explorer and read your history. Pay someone from that wallet, and they can see everything else too.
Mixing breaks that link. The stated aim was to protect ordinary people, such as donors, staff and businesses that don't want rivals reading their payments.
How Tornado Cash Uses Smart Contracts and Zero-Knowledge Proofs
You deposit a fixed amount of ETH, such as 0.1, 1, 10 or 100. The contract gives you a secret note. Later, you withdraw to a fresh address using a zero-knowledge proof.
That's a cryptographic method that proves you made a valid deposit without revealing which one. Identical deposit sizes keep every entry looking alike.
How Does Tornado Cash Make Crypto Transactions Harder to Trace?
It cuts the obvious link between sender and receiver. Both the deposit and the withdrawal stay on the public chain, but nothing there shows which belongs to whom.
The Role of Deposit and Withdrawal Addresses
Deposits come from one address. Withdrawals land in another. More depositors create a bigger anonymity set, meaning the crowd a withdrawal could belong to.
Users can weaken that cover themselves. Withdrawing the same amount minutes after depositing, or reusing a known address, can point straight back to them.
What Blockchain Analytics Can and Cannot Reveal
Analysts can see every deposit and withdrawal. They can't read the secret note that links the two.
Why Do Hackers Still Use Tornado Cash?
The Tornado Cash pool contracts are immutable, so nobody can switch them off. Anyone can still use them, including thieves.
Moving Funds After a Crypto Hack
After a crypto hack, stolen coins sit in a wallet everyone is watching. A mixer is an attempt to break that trail. In 2022, US sanctions authorities said the service had helped launder more than $7 billion since 2019, including $455 million stolen by North Korea's Lazarus Group. Those are allegations, not court findings.
Obscuring Transaction Links Across Wallets
Treasury's March 2026 report describes the usual pattern. Hackers split loot across wallets, mix it, then bridge to other chains or swap into stablecoins.
Why Mixing Funds Does Not Guarantee Escape From Investigators
Mixing isn't invisibility. The deposit itself is public, and exchanges can flag coins linked to known thefts. Investigators also combine on-chain clues with evidence from outside the blockchain.
Tornado Cash Sanctions and the Legal Controversy Explained
Why US Authorities Targeted Tornado Cash
In August 2022, the US Treasury's sanctions office blacklisted the protocol, arguing it enabled anonymous transfers without checking where funds came from.
Six users sued. In November 2024, the Fifth Circuit ruled that the immutable smart contracts weren't "property" the law could sanction. Then, in March 2025, Treasury removed the sanctions.
What the Legal Dispute Means for Crypto Privacy
Delisting didn't end the case against Tornado Cash developer Roman Storm. In August 2025, a New York jury convicted him of conspiring to run an unlicensed money transmitting business, which carries up to five years.
Jurors deadlocked on the laundering and sanctions counts. Retrial is set for April 26, 2027. As of October 26, 2026, the latest reports show his acquittal motion still undecided.
The core question: can a developer be liable for what strangers do with immutable code?
Is Tornado Cash Illegal to Use?
There's no single yes or no. Legality depends on where you live, the rules in force and what you do with it. In the US, the sanctions on the protocol are gone, yet prosecutors still pursue some people behind it.
Sending stolen or sanctioned funds through any mixer can create serious liability. Check official guidance for your country, or ask a licensed lawyer, before using any mixer.
Can Tornado Cash Transactions Be Traced by Blockchain Analysts?
Analysts build transaction graphs that map how funds move between addresses. They cluster wallets that appear to share an owner, using timing, amounts and gas fee habits.
Exchanges add another layer. Compliance teams screen deposits and may review or freeze funds with a mixer in their history. Off-chain evidence often does the heavy lifting, such as exchange account records.
But visibility isn't identity. A public address is only a string of characters until something ties it to a person.
What Risks Should Crypto Users Understand?
Even careful users face practical risks:
Legal exposure. Rules differ by country and can change quickly.
Flagged wallets. Funds linked to a mixer can trigger exchange reviews or delayed withdrawals.
Scams. Fake mixer sites and phishing links copy popular tools to drain wallets.
Lost notes. Without the secret note, a deposit may be impossible to withdraw.
Check official Treasury notices before acting, since sanctions lists change.
Basic wallet security matters too: verify URLs, use a hardware wallet and never share your seed phrase.
Tornado Cash vs Traditional Crypto Transactions
Factor | Regular transfer | Mixer pool |
Visibility | Sender, receiver and amount are public | Deposit and withdrawal are public, the link is hidden |
Privacy | Low | Higher, depends on pool size and habits |
Custody | You hold your keys | You hold a secret note |
Compliance | Clean trail for exchanges | May trigger flags or reviews |
The trade-off is simple: more privacy, more friction and more scrutiny.
Expert Opinion: What Does Tornado Cash Mean for Crypto Privacy?
Both sides have a point. Treasury's report acknowledged that lawful users may want mixers for privacy and didn't recommend new limits on non-custodial ones. It also says North Korean hackers and ransomware crews rely on mixers, bridges and swaps.
The fair reading is that financial privacy is a real need, and an open pool like Tornado Cash serves thieves too. Law will keep trying to separate the tool from the conduct. Watch the Storm retrial, because it may shape how developers view that line.
Conclusion
Tornado Cash is a non-custodial mixer that uses smart contracts and zero-knowledge proofs to weaken the visible link between sender and receiver.
Hackers still use it because the contracts stay available and mixing complicates tracing. It doesn't make anyone untouchable, though, since investigators pair blockchain analytics with other evidence.
The legal picture remains open: sanctions are lifted, but the Storm case continues. Check current law in your country before going near any mixer.
Disclaimer: This article is for information only and isn't financial, legal or investment advice. Crypto is high risk and laws change quickly. Do your own research before making decisions.
