What Are Coin Mixers and How Do They Work? – Decrypt

Coin mixers have captured the eye of each the cryptocurrency neighborhood and regulators because the battle for privateness ramps up.

In 2021, the founding father of coin mixer Bitcoin Fog was arrested on fees together with cash laundering and working a cash transmission enterprise and not using a license.

A yr later, the U.S. Treasury Division issued sanctions towards Twister Money, an Ethereum coin mixing service, successfully banning Individuals from utilizing it.

In a landmark ruling in November 2024, the U.S. Fifth Circuit Court docket dominated that the Treasury had overstepped by sanctioning Twister Money’s sensible contracts, though its broader designation remained intact.

In a reversal of its 2022 determination, the Treasury introduced in March 2025 that it had delisted Twister Money from its listing of events sanctioned by the Workplace of Overseas Property Management, or OFAC.

However what do coin mixers like Twister Money and Bitcoin Fog do—and why do folks use them? On this article, we’ll study the expertise behind mixers and their reputable and illegitimate makes use of.

What’s a coin mixer, and why use them?

A coin mixer is a service that permits customers to obfuscate the origin and vacation spot of transactions. Customers ship cryptocurrency to the service, have that crypto blended with different cash or tokens, after which ship the equal quantity of “blended” cash to a recipient deal with, hiding the connection between the sender and recipient.

There are a lot of reputable makes use of for this sort of service. Simply as you could not need your employer to know the intimate particulars of each financial institution or bank card transaction that you’ve got ever made, you may additionally not need your employer—or anybody else, for that matter—to know each element of each crypto transaction you’ve got ever made both.

However because the adoption of crypto and blockchain instruments grows, real-world identities have gotten more and more linked to blockchain addresses—with each buy, switch, or interplay related to these addresses laid naked on a public, clear, distributed ledger. And that is the place coin mixers are available in.

Nevertheless, this capacity to masks the identification of wallets and obfuscate transactions makes coin mixers a sexy device for cybercriminals, and thus a goal for regulation enforcement.

Whereas politicians and regulation enforcement have railed towards using cryptocurrency in legal enterprises, coin mixers occupy a grey space between facilitating cash laundering and preserving the precise to privateness. Due to blockchain’s permissionless and clear nature, some crypto customers depend on the added privateness that coin mixers present.

Privateness advocates argue that coin mixers are particularly helpful, even needed, in circumstances the place an individual’s actions—like journalism, civil disobedience, and protest—can put that individual in danger. Due to this, they require higher privateness of their crypto transactions.

Alternatively, regulation enforcement and authorities companies see coin mixers as a means for criminals to launder cash utilizing cryptocurrency, and companies like Twister Money as a way of obscuring the place the funds originated.

In its announcement of the sanctions towards Twister Money, the Treasury Division stated that criminals had used Twister Money to launder cash, saying the service processed greater than $7 billion price of digital foreign money since its creation in 2019. In response to blockchain analytics agency Elliptic, round $1.5 billion of that determine was linked to illicit exercise.

Amongst these illicit funds, the Treasury stated, had been a mixed $103.8 million stolen from crypto bridging companies by Lazarus Group, a state-sponsored North Korean cybercriminal group.

A November 2024 ruling by the U.S. Fifth Circuit Court docket discovered that the Treasury had overstepped its authority, and that Twister Money’s immutable sensible contracts “aren’t property as a result of they aren’t able to being owned.” The choice reversed a decrease court docket ruling, noting that protocols constructed on sensible contracts can’t be categorized as companies as a result of they function with out “human intervention.”

In March 2025, the Treasury reversed course, eradicating Twister Money from its listing of sanctioned entities. “Based mostly on the Administration’s assessment of the novel authorized and coverage points raised by use of monetary sanctions towards monetary and business exercise occurring inside evolving expertise and authorized environments, we now have exercised our discretion to take away the financial sanctions towards Twister Money as mirrored in Treasury’s Monday submitting in Van Loon v. Division of the Treasury,” the Treasury stated in an announcement.

A month later, a federal court docket dominated that the Treasury’s actions had been “illegal,” completely barring OFAC from reinstating sanctions towards Twister Money. Decide Robert Pitman, of The U.S. District Court docket for the Western District of Texas, positioned an order compelling the Treasury to be “completely enjoined from implementing” sanctions on the coin mixer, delivering a powerful victory for privateness advocates.

In July 2025, the usCourt of Appeals for the Eleventh Circuit dismissed an attraction filed by crypto advocacy group Coin Middle, through which it argued that the Treasury Division had exceeded its statutory authority in sanctioning Twister Money. The court docket granted a joint movement to vacate the judgement and remand with directions to dismiss, with each events agreeing that the attraction was “moot” following OFAC’s March determination to take away sanctions towards the coin mixer.

Examples of coin mixers

Twister Money: Based in 2019 by Alexsey Pertsev and Roman Storm, this mixer was sanctioned by the U.S. Treasury Division in 2022. Twister Money completely companies the Ethereum Community and is non-custodial.
Samourai Pockets: A non-custodial Bitcoin-only mixer based in 2015 by Keonne Rodriguez and William Longergan Hill, its founders had been arrested and charged with conspiracy to commit cash laundering in 2024.
Wasabi Pockets: Based by pseudo-anonymous zkSNACKs in 2018, it makes use of the ZeroLink protocol to create transaction privateness. Wasabi blocked U.S. residents from utilizing the mixer in 2024 after the founders of Samourai Pockets had been arrested.
Bitcoin Fog: Based in 2011 by Roman Sterlingov, Bitcoin Fog was a custodial mixer, and held person funds within the course of of blending them. Sterlingov was convicted of cash laundering in 2024.

How do coin mixers work?

Earlier than Twister Money was taken down, it used sensible contracts to simply accept token deposits from one deal with and allow their withdrawal from a distinct deal with.

Different coin mixers function in an analogous means, with sensible contracts that work as a pool the place all of the deposited tokens get blended collectively. When funds are withdrawn from these swimming pools, the on-chain hyperlink between the supply and the vacation spot is damaged, anonymizing the transaction.

These sorts of coin mixers are sometimes non-custodial, that means there isn’t any third-party management of the pockets and funds, merely the creation of the sensible contracts.

As a result of these companies use no middleman, they’re reliably impartial—however that additionally means they could be a tempting device for cybercriminals seeking to launder stolen crypto, as within the case of Lazarus Group.

Coin mixers: a timeline

October 2011: Bitcoin tumbler Bitcoin Fog is launched.
December 2019: Coin mixer Twister Money is launched.
April 2021: The U.S. Division of Justice broadcasts the arrest of Bitcoin Fog operator Roman Sterlingov.
August 2022: The U.S. Treasury Division sanctions Ethereum coin mixer Twister Money. Days later, developer Alexey Pertsev is arrested in Amsterdam on cash laundering fees.
March 2024: Bitcoin Fog operator Roman Sterlingov is convicted of cash laundering.
April 2024: U.S. authorities arrest and cost the founders of Bitcoin mixer Samourai Pockets, accusing them of conspiracy to commit cash laundering.
Could 2024: Wasabi Pockets broadcasts the preemptive closure of its mixing service, banning U.S. clients from utilizing its companies. Concurrently, Phoenix Pockets pulls its app from shops within the U.S., whereas {hardware} pockets Trezor broadcasts the discontinuation of its Coinjoin characteristic.
November 2024: The U.S. Fifth Circuit Court docket guidelines that Twister Money’s immutable sensible contracts can’t be categorized as “property.”
March 2025: The U.S. Treasury lifts its sanctions towards Twister Money.
April 2025: A U.S. federal court docket choose points an order completely blocking the Treasury from reinstating sanctions towards Twister Money.
July 2025: A U.S. Court docket of Enchantment grants a joint movement to finish crypto advocacy group Coin Middle’s attraction towards OFAC’s sanctions.

Reliable use circumstances of coin mixers

Let’s say there’s a enterprise proprietor and crypto fanatic named Robert who needs to ship Ethereum to a hacktivist group working out of Ukraine. Robert would not need his donation to be traced again to him, so he makes use of a coin mixer.

Robert goes to the coin mixer web site and deposits the Ethereum he needs to donate. The despatched quantity is deposited into the mixer’s sensible contract and pooled with the opposite hundred, hundreds, and even tens of millions of transactions already in its pool. After receiving affirmation that the deposit was profitable, Robert goes to the withdraw tab, enters the recipient’s deal with into the mixer, and sends the Ethereum from the mixer.

The Ethereum is then despatched from the blending to the recipient. On the receiving finish, the deal with proven is that of the mixer and never the unique sender’s deal with, anonymizing the transaction.

If this hypothetical state of affairs sounds acquainted, it is primarily based on a tweet from Ethereum co-founder Vitalik Buterin, posted after the Treasury Division sanctioned Twister Money.

The way forward for coin mixers

The controversy over crypto privateness continues to rage, regardless of the collection of authorized circumstances and sanctions towards coin mixers.

The November 2024 ruling that immutable sensible contracts can’t be categorized as “property” was hailed by crypto and privateness advocates as a landmark second, that means that self-executing code that operates with none administrative management can’t be topic to sanctions.

More moderen initiatives like Railgun goal to offer customers on-chain privateness, but in addition make sure that they continue to be compliant within the eyes of the regulation.

Railgun will not be a conventional mixer; it doesn’t combine cash from a number of sources collectively, and its founders consider it avoids the pitfalls that finally led to mixers getting sanctioned or sued.

It additionally makes use of “Non-public Proof of Innocence” to make sure dangerous actors can’t use the platform for illicit functions. For instance, on July 11, 2024, a infamous crypto drainer referred to as Inferno Drainer tried to make use of Railgun to launder 174 ETH. Nevertheless, Railgun recognized that the pockets was tied to a nasty actor and blocked the transactions.

Whether or not crypto privateness initiatives’ efforts to create legally compliant mixing companies will mollify lawmakers is open to debate. One factor’s for sure, although—privateness advocates will proceed to combat to make sure that crypto is not a panopticon.

As Lia Holland, Campaigns & Communications Director at Struggle for the Future, wrote in 2022: “Allow us to be clear, hackers and cybercriminals, in addition to people who help them, are deplorable and needs to be stopped—however not in a means that compromises human rights and the primary modification.”

This text was first written in August 2022 and up to date in July 2025.