Bitcoin Privacy with CoinJoinA Bitcoin privacy technique where multiple users combine inputs and outputs into one transaction to make ownership links harder to analyze.Glossary →: Wasabi Wallet Guide
Bitcoin is public by default. Every transaction lands on a permanent ledger. Firms such as Chainalysis, Elliptic, and TRM Labs trace BTC between addresses. If your coins came from a KYCKnow Your Customer rules require users to submit identity information such as passports, selfies, addresses, or phone numbers before accessing a service.Glossary → exchange, that exchange can tie your name to the UTXOAn unspent transaction output is a discrete chunk of cryptocurrency in Bitcoin-like systems. Wallet privacy depends heavily on how these outputs are spent and merged.Glossary →. CoinJoin breaks that link. The WabiSabi research paper explains the protocol behind Wasabi Wallet.
Key points
- Wasabi's default coordinator, zkSNACKs, shut down in May 2024. Use a third-party coordinator. Check wabisabi.io for active options.
- Never spend a CoinJoined UTXO with a non-CoinJoined UTXO in the same transaction. That merge can expose both.
- An anonScore of 50 or more is meaningful. Aim higher for UTXOs that came from KYC exchanges.
Bitcoin is traceable by design
Bitcoin uses the unspent transaction output, or UTXO, model. Each transaction spends one or more UTXOs and creates new ones. Because the ledger is public, anyone can trace a UTXO back to its origin and, through exchange records, often to a real identity.
Common heuristics used by chain analytics:
- Common input ownership: if two UTXOs are spent together, they likely belong to the same wallet.
- Change address detection: analysts identify the change output by script type, round numbers, and address reuse.
- Dust attacks: tiny amounts get sent to your address so analysts can watch when you spend them.
- Address reuse: the easiest way to link multiple transactions to one entity.
CoinJoin breaks the input-to-output link
CoinJoin combines many users' transactions into one transaction with many inputs and many equal-value outputs. Because the outputs match in value, an outside observer cannot tell which input maps to which output.
The anonymity set is the number of participants whose outputs look the same as yours. A set of 5 means a 1-in-5 guess. More rounds raise that number. Repeated rounds can push anonymity sets above 100.
Wasabi vs Sparrow
Both are real CoinJoin tools for Bitcoin. Choose based on your skill level and preferred coordinator model.
Wasabi Wallet. Desktop wallet for Windows, Mac, and Linux with a built-in CoinJoin coordinator interface using the WabiSabi protocol. The original zkSNACKs coordinator shut down in May 2024 after OFACThe US Office of Foreign Assets Control administers sanctions lists and restrictions that many banks, exchanges, and crypto services enforce worldwide.Glossary → pressure. Users now connect to third-party coordinators. Wasabi is the simpler choice if CoinJoin is the main job.
Sparrow Wallet. Desktop wallet with Whirlpool CoinJoin integration, Samourai's protocol. After Samourai Wallet's arrest in 2024, Sparrow's Whirlpool coordinator became community-run. Sparrow suits users who want deeper UTXO management alongside CoinJoin.
⚠ Important, May 2024 change: Wasabi's default coordinator, zkSNACKs, shut down. The software still works, but you must set a third-party coordinator. Active options in early 2026 include WabiSabi coordinators listed at wabisabi.io and community-run instances. Check status before use. Low participation means a weak anonymity set.
Set up Wasabi the right way
Download and verify Wasabi
Download from wasabiwallet.io. Verify the PGP signature before installing. Wasabi publishes its signing key on the site. On Linux: gpg --verify WasabiWallet.deb.asc. Do not skip verification. Wallet software is a high-value target.
Create a new wallet
Open Wasabi and create a new wallet. It makes a BIP84 SegWit native bech32 wallet by default. Write down the 12-word seed phraseA set of wallet recovery words that can recreate a private key set. Anyone with the phrase can usually control the funds.Glossary → on paper. Do not store it digitally. Set a strong wallet password.
If your BTC is already on an exchange, do not import an exchange-linked seed into Wasabi. Make a fresh wallet first, then withdraw BTC into it. CoinJoin starts there.
Receive BTC to a fresh address
In the Receive tab, generate an address. Send the BTC you want to CoinJoin to that address. Wait for at least one confirmation. The UTXO then appears in your wallet.
Configure a coordinator if needed
In Wasabi settings, find the CoinJoin coordinator field. If the default is empty or throws an error, enter a community coordinator URL. Check Wasabi GitHub discussions or wabisabi.io for active coordinators. More participants usually means a stronger anonymity set.
Start CoinJoin
Open the CoinJoin tab. Select the UTXOs you want to mix. Set your anonymity target. Wasabi calls it the anonScore target. A target of 5 is weak. 50 or more is meaningful. Higher targets take more rounds and more time.
Start the process. Wasabi handles round participation automatically. Your wallet must stay open and connected. Leave it running overnight or through a weekend if you want a higher score.
Spend from CoinJoined outputs only
After CoinJoin completes, Wasabi shows an anonScore for each UTXO. When you spend, use Coin Control to select only CoinJoined UTXOs. Never combine a CoinJoined UTXO with a non-CoinJoined UTXO in one transaction. That is UTXO merging, and it can expose both.
Coin control is not optional
Most wallets choose UTXOs automatically when you spend. That is convenient and bad for privacy. If the wallet combines a CoinJoined UTXO with a non-CoinJoined UTXO, chain analysisThe practice of tracing blockchain transactions, clustering addresses, and linking on-chain activity to real identities using heuristics and external data.Glossary → can link them through common input ownership and undo the mix.
Use manual coin control every time. In Wasabi, UTXOs are tagged with their anonScore. Spend high-score UTXOs. If you must combine outputs, combine only ones with similar scores and history.
Keep TorThe Tor network uses onion routing to obscure IP addresses and browsing paths by relaying traffic through multiple volunteer-run nodes.Glossary → enabled
Wasabi routes traffic through Tor by default. Leave it on. That keeps your IP from being tied to your wallet or your CoinJoin participation. If Tor breaks, fix Tor. Do not disable it.
Provider comparison
| Tool | Protocol | Coordinator | Coin Control | Tor Built-in | Platform | Complexity |
|---|---|---|---|---|---|---|
| Wasabi | WabiSabi | Third-party (post-2024) | Yes (anonScore) | Yes | Desktop | Medium |
| Sparrow | Whirlpool | Community-run | Yes (full) | Manual config | Desktop | Medium–High |
| JoinMarket | JoinMarket | Decentralized (P2P) | Yes | Yes | CLI / Desktop | High |
✓ JoinMarket has no central coordinator. It runs peer to peer over IRC relays on Tor, which makes it harder to attack at the coordinator level. It is also the hardest option to set up. For most people, Wasabi with a solid community coordinator is the best place to start.
Follow the money
The chain analysis industry profits by undoing what CoinJoin does. Chainalysis alone makes about $90M a year selling Bitcoin tracing to governments. CoinJoin is one of the behaviors its Reactor product tries to unwind.
- Chainalysis
- ~$90M ARR · Series F ($170M raised). Reactor recovers KYC links via UTXO heuristics. Clients: FinCENThe US Financial Crimes Enforcement Network is the Treasury bureau that receives SARs, issues AML guidance, and pressures crypto businesses into surveillance compliance.Glossary →, FBI, IRS-CI, OFAC + 70+ agencies.
- Tornado Cash precedent
- OFAC sanctioned the smart contract itself (August 2022). $100M settlement. Open-source code sanctioned. Developer Alexey Pertsev: 5-year prison sentence.
- Samourai Wallet
- Founders arrested April 2024 (US DOJ). Whirlpool coordinator charged with money transmission. Individual users unaffected. Software still runs locally.
- CoinJoin legal status
- Individual use unprosecuted in any jurisdiction. Anonymity set 50+ = meaningful chain resistance. XMR via swap: structurally unanalyzable by design.
Information is provided for educational purposes. Always verify provider terms. Not financial advice. Affiliate disclosure.
Frequently Asked Questions
Is CoinJoin legal to use?
Using CoinJoin as an individual is legal in the US, EU, UK, and most jurisdictions. Enforcement has targeted coordinators, not users. The DOJ’s 2024 case against Samourai Wallet focused on the operators of the Whirlpool coordinator, not people who used it. As of 2026, no jurisdiction has prosecuted individual CoinJoin use for personal transaction privacy.
What happened to Wasabi's zkSNACKs coordinator?
The zkSNACKs coordinator shut down in May 2024 after OFAC pressure. Wasabi Wallet still works, but you now need a third-party community coordinator. Active coordinators are listed at wabisabi.io and in Wasabi’s GitHub discussions. Low coordinator participation means a weak anonymity set, so check activity before you start.
How many CoinJoin rounds do I need for meaningful privacy?
Wasabi uses anonScore to show the effective anonymity set of each UTXO. A score of 5 is weak. A score of 50 or more is meaningful against most chain analysis. Higher scores take more rounds and more time, sometimes days for larger amounts. For high-sensitivity use, combine multiple Wasabi rounds with a later swap to Monero through a no-KYC service.
What is UTXO merging and why is it dangerous after CoinJoin?
UTXO merging means spending a CoinJoined UTXO together with a non-CoinJoined UTXO in one transaction. That breaks privacy fast. Chain analysis applies the common input ownership heuristic and assumes all inputs belong to the same wallet. Merge a clean post-mix UTXO with a KYC-linked UTXO and you undo the CoinJoin. Use Wasabi’s coin control and never combine pre-mix with post-mix outputs.