Mixing (Tumbling)
Definition
A service or protocol that accepts cryptocurrency inputs from multiple users and returns equivalent outputs in a way designed to break the linkage between sending and receiving addresses. CoinJoin is the most common Bitcoin mixing protocol.
- Common protocol
- CoinJoin (Bitcoin)
- Goal
- Break address-linkage between sender and receiver
- Also known as
- Tumbler
- Investigative counter
- Clustering heuristics, taint analysis, subpoenaing operator logs
Common questions
Can a mixer be fully de-anonymised?+
Not always, but poor implementations, small anonymity sets, timing correlation, or reused change addresses often let analysts partially trace funds through a mixer, especially when combined with exchange KYC data at the cash-out point.
Is using a mixer itself illegal?+
This varies by jurisdiction. Some countries treat mixing services as money-transmission businesses requiring licensing, and several operators have been prosecuted for facilitating money laundering rather than for the mixing technique itself.
Related terms
- Attribution Database
- A commercial or law-enforcement dataset that maps known addresses or address clusters to real-world entities: exchanges, darknet markets, ransomware operators, sanctioned individuals,...
- Change-Address Heuristic
- The inference that one output from a Bitcoin transaction (usually the smaller one, to a fresh address) is change returning to the...
- Co-Spend Heuristic
- The inference that when multiple Bitcoin inputs appear in one transaction, all those input addresses are controlled by the same entity, because...
- De-Anonymisation
- The process of linking a pseudonymous address or cluster to a real-world identity. Most commonly achieved through exchange KYC records, but also...
- Peel Chain
- A transaction pattern where one large input is repeatedly split, sending most of the value one hop forward and a small remainder...