Types of Mixers and Tumblers

Core idea

Mixing services fall into five recognizable categories that differ in custody model, technical mechanism, and risk level. Classifying a service helps an investigator predict its behavior and choose the analytical approach most likely to defeat it.

Components

• Centralized mixers: operated by a central entity that takes custody of funds. Examples: ChipMixer, BitCloak, Hola, Blender.io (closed). Risk: High.
• Decentralized mixers: smart contract based mixing without a central custodian. Examples: Tornado Cash (Ethereum), Railgun, decentralized CoinJoin wallets. Risk: High.
• CoinJoin wallets: combine multiple transactions into one to improve privacy. Examples: Wasabi Wallet, Samourai Wallet, JoinMarket. Risk: Medium.
• Protocol-based mixers: built into DeFi protocols or liquidity pools. Examples: Thorchain, Secret Network, MimbleWimble protocol. Risk: High.
• Cross-chain mixers: use bridges and swaps to move funds across chains and break traceability. Examples: AnySwap, Synapse, Multichain. Risk: High.

When to use

Use when categorizing a service encountered in a trace, scoping which explorers and techniques you will need, or assigning a preliminary risk rating.

Related

Mixers and Tumblers, Mixing Obfuscation Techniques, Legal and Regulatory Landscape for Mixers