Advix Blog

Understanding Cryptocurrency Mixers

Compliance Crypto
Cryptocurrency mixers, also known as tumblers, are tools designed to enhance the privacy of cryptocurrency transactions by obscuring the origins and destinations of digital assets. While they offer legitimate privacy benefits, they also present significant challenges for anti-money laundering (AML) efforts. This article will explore how these mixers work and the AML challenges they present.

How Cryptocurrency Mixers Work

Cryptocurrency mixers operate by pooling together funds from multiple users and then redistributing them in a way that makes it difficult to trace the original source and final destination of the funds. The following is a simplified process of how they function:
  1. Deposit: Users send their cryptocurrency to the mixer's address.
  2. Mixing: The mixer combines the deposited funds with those from other users. This mixing process uses various techniques such as breaking the funds into smaller denominations and using multiple intermediary wallets​.
  3. Redistribution: After a certain period, the mixed funds are redistributed to the users' specified addresses, minus a small fee. This redistribution breaks the link between the sender and receiver​.
There are two main types of mixers:
  • Centralised Mixers: These involve a trusted third party that manages the mixing process. Users must trust that the mixer does not keep transaction logs that could later reveal transaction details​.
  • Decentralised Mixers: These use smart contracts and blockchain technology to automate the mixing process without the need for a central intermediary, enhancing security and privacy​.

AML Challenges

While mixers provide privacy for legitimate users, they also create significant challenges for AML efforts:
  1. Obfuscation of Illicit Activities: Mixers can be used to launder money obtained through illegal activities, such as hacks or fraud. By breaking the transaction trail, mixers make it difficult for authorities to trace the origin of the illicit funds​​.
  2. Regulatory Evasion: Many mixers operate outside the regulatory frameworks that govern traditional financial institutions. For instance, the U.S. Financial Crimes Enforcement Network (FinCEN) requires mixers to register as money transmitters, but compliance is rare​.
  3. High-Profile Cases: There have been notable instances where mixers were used in large-scale money laundering schemes. For example, Tornado Cash was sanctioned by the U.S. Treasury for its role in laundering over $7 billion, including funds linked to the North Korean Lazarus Group​.

Real-Life Examples

  • Tornado Cash: This decentralised mixer was sanctioned by the U.S. Treasury's Office of Foreign Assets Control (OFAC) for its involvement in laundering billions of dollars, including proceeds from significant cyber heists​​.
  • Another mixer that was sanctioned for similar reasons, was used to launder funds from the infamous Axie Infinity hack, where North Korean hackers stole around $620 million​.


Cryptocurrency mixers present a duality in the digital finance landscape. While they provide users with the necessary privacy, they also facilitate money laundering and other illicit activities, posing substantial challenges for AML compliance. It is crucial for regulators and AML specialists to understand the operation of these mixers and develop strategies to mitigate their misuse while balancing the need for privacy in legitimate transactions.
By staying informed and vigilant, we can better navigate the complexities of cryptocurrency transactions and enhance the effectiveness of AML efforts in this evolving digital landscape.