Overview
Cryptocurrency mixers (also called tumblers) are services that blend cryptocurrency from multiple sources to obscure the transaction trail. While they have legitimate privacy uses, they are frequently used to launder stolen funds.
Interacting with known mixer addresses can result in your own wallet being flagged by exchanges and compliance tools.
How Mixers Work
- Deposit: User sends crypto to mixer
- Pooling: Funds are combined with others
- Redistribution: Different coins returned to user
- Obfuscation: Original transaction trail is broken
Types of Mixers
Centralized Mixers
- Operated by a single entity
- Require trust in the operator
- Examples: Historical services (many now defunct)
Decentralized Mixers
- Smart contract-based
- No central operator
- Example: Tornado Cash (sanctioned by OFAC)
Cross-Chain Bridges
- Move funds between blockchains
- Can obscure origin of funds
- Examples: Various bridge protocols
Detection Indicators
| Tag | Severity | Description |
|---|
mixer | High | Address associated with mixing service |
associated_mixer | Medium | Has transacted with known mixers |
tornado | High | Tornado Cash interaction detected |
associated_tornado | Medium | Connected to Tornado Cash users |
fixedfloat | Medium | FixedFloat service usage detected |
simpleswap | Medium | SimpleSwap service usage detected |
minter-fundflow-mixer | High | Token minter fund flow involves mixers |
Regulatory Context
- OFAC Sanctions: Tornado Cash was sanctioned in August 2022
- Exchange Compliance: Most exchanges block mixer-associated funds
- Legal Risk: Using mixers with illicit funds is money laundering
API Example
curl -X GET "https://api.webacy.com/addresses/0x123...?chain=eth" \
-H "x-api-key: YOUR_API_KEY"
{
"overallRisk": 85.0,
"issues": [
{
"tag": "associated_mixer",
"severity": "medium",
"description": "Address has transacted with known mixer services"
}
]
}
Risk Assessment
When evaluating mixer-associated addresses:
- Direct usage: Highest risk - address directly used mixer
- One hop away: High risk - received funds from mixer user
- Two+ hops: Lower but still flagged - contaminated funds
- Timing: Recent mixer use is higher risk than historical
