Multiple Rounds of Mixing for Enhanced Privacy

One of the most powerful features of JoinMarket mixing is the ability to perform multiple rounds of mixing. Each round further obfuscates the transaction trail by combining your coins with different sets of participants. The more rounds you complete, the harder it becomes for an adversary to trace your funds.

For example, if you mix your coins in three separate rounds with different participants each time, an outside observer would need to analyze three separate transactions to attempt to link your original input to the final output. This plausible deniability is a key advantage of JoinMarket.

Fee Structure and Incentives

JoinMarket operates on a fee-based system where makers earn Bitcoin for providing liquidity. The fee structure is designed to balance cost and efficiency:

• Maker Fees: Makers set their own fee rates, typically ranging from 0.1% to 1% of the mixed amount. Higher fees may attract more takers but reduce profitability.
• Taker Fees: Takers pay the fee set by the maker. The total cost depends on the amount being mixed and the number of rounds.
• Dynamic Pricing: JoinMarket’s software adjusts fees based on market demand, ensuring competitive pricing.

This incentive structure ensures that the network remains active and liquid, even during periods of low demand.

Setting Up JoinMarket: A Step-by-Step Guide

Prerequisites: What You’ll Need

Before setting up JoinMarket mixing, you’ll need the following:

• A Bitcoin wallet with funds to mix (preferably a non-custodial wallet like Electrum or Wasabi).
• A Bitcoin full node (optional but recommended for enhanced privacy).
• A computer running Linux, macOS, or Windows (JoinMarket is cross-platform).
• Basic familiarity with command-line interfaces (CLI).

Step 1: Downloading and Installing JoinMarket

JoinMarket is open-source software available on GitHub. Follow these steps to install it:

1. Download the Latest Release: Visit the JoinMarket releases page and download the appropriate version for your operating system.
2. Extract the Files: Unzip the downloaded archive to a directory of your choice.
3. Install Dependencies: JoinMarket requires Python 3.6+ and several Python libraries. On Linux, you can install them with:

sudo apt-get update
sudo apt-get install python3 python3-pip python3-venv

4. Set Up a Virtual Environment (Recommended): To avoid conflicts with other Python packages, create a virtual environment:

python3 -m venv joinmarket-venv
source joinmarket-venv/bin/activate

5. Install JoinMarket: Navigate to the JoinMarket directory and run:

pip install -r requirements.txt

Step 2: Configuring JoinMarket

After installation, you’ll need to configure JoinMarket to connect to the Bitcoin network and set your mixing preferences.

1. Edit the Configuration File: Open joinmarket.cfg in a text editor. Key settings include:
• network: Set to mainnet for Bitcoin mainnet.
• rpc_user and rpc_password: Your Bitcoin node’s RPC credentials (if using a full node).
• blockchain_source: Set to local if using a full node, or electrum if using an Electrum server.
2. Set Up Your Bitcoin Wallet: JoinMarket supports several wallet types, including Electrum and Bitcoin Core. If using Electrum, ensure your wallet is loaded and synchronized.
3. Fund Your Wallet: Transfer the Bitcoin you wish to mix to your JoinMarket wallet. Avoid using exchange addresses directly, as they may be flagged by surveillance firms.

Step 3: Running JoinMarket as a Maker or Taker

Once configured, you can use JoinMarket in two primary roles: maker or taker.

Running as a Maker (Liquidity Provider)

Makers provide liquidity by offering to mix their coins for a fee. To start:

1. Generate a New Address: Use your wallet to generate a new Bitcoin address where you’ll receive mixing fees.
2. Set Your Fee and Minimum Taker Size: Edit your joinmarket.cfg or use the sendpayment.py script to set your preferences.
3. Start the Maker Bot: Run the following command to start the maker bot:

python scripts/sendpayment.py --marketmaker

4. Monitor Your Orders: The bot will automatically match takers and execute transactions. You can monitor your orders in the orderbook file.

Running as a Taker (Privacy Seeker)

Takers pay to have their coins mixed. To start:

1. Select a Maker: Use the taker.py script to browse available makers and their fee rates.
2. Choose Your Mixing Strategy: Decide on the number of rounds and the amount to mix. More rounds = higher privacy but higher cost.
3. Execute the Mix: Run the taker script with your chosen parameters:

python scripts/taker.py --amount 0.1 --rounds 5 --mixdepth 0

4. Verify the Transaction: Once the mix is complete, verify the transaction on a blockchain explorer like Blockstream.info.

Step 4: Best Practices for Secure Mixing

To maximize privacy and security when using JoinMarket mixing, follow these best practices:

• Use a Dedicated Wallet: Create a new wallet specifically for mixing to avoid linking your identity to other transactions.
• Avoid Reusing Addresses: Always generate new addresses for each mixing round.
• Use Tor or a VPN: Route your JoinMarket traffic through Tor or a VPN to prevent IP-based tracking.
• Monitor Transaction Fees: High Bitcoin network fees can make mixing expensive. Use tools like Mempool.space to check fee rates.
• Keep Your Software Updated: JoinMarket is actively developed, so regularly update to the latest version to benefit from security patches and new features.

JoinMarket vs. Other Bitcoin Mixing Methods

JoinMarket vs. Centralized Mixers

Centralized mixers (e.g., BitcoinMix, ChipMixer) are popular due to their ease of use, but they come with significant drawbacks:

While centralized mixers may be convenient, they are vulnerable to exit scams, regulatory shutdowns, and blockchain analysis. JoinMarket mixing, on the other hand, eliminates these risks by removing the need for a trusted third party.

JoinMarket vs. Wasabi Wallet’s CoinJoin

Wasabi Wallet is another popular Bitcoin privacy tool that implements CoinJoin. While both JoinMarket and Wasabi use the same underlying protocol, they differ in approach:

• JoinMarket: Decentralized, market-based, and highly customizable. Users can act as makers or takers and set their own fees.
• Wasabi Wallet: Centralized coordinator (but non-custodial), user-friendly, and designed for one-time CoinJoins. Fees are fixed, and users cannot act as makers.

For users seeking maximum privacy and control, JoinMarket mixing is the superior choice. However, Wasabi Wallet is more accessible for beginners due to its intuitive interface.

JoinMarket vs. Samourai Wallet’s Whirlpool

Samourai Wallet’s Whirlpool is a CoinJoin implementation designed for frequent mixing. Like JoinMarket, it uses a decentralized approach, but with key differences:

• JoinMarket: Open marketplace, flexible fee structure, and supports multiple rounds of mixing.
• Whirlpool: Fixed-size CoinJoins (e.g., 0.01 BTC, 0.05 BTC), automated mixing, and integration with Samourai’s other privacy tools (e.g., Stonewall, PayJoin).

Whirlpool is ideal for users who want automated, frequent mixing, while JoinMarket mixing offers more granular control over the mixing process.

Advanced Strategies for JoinMarket Mixing

Maximizing Privacy with Multiple Rounds

The most effective way to enhance privacy with JoinMarket mixing is to perform multiple rounds. Each round combines your coins with different participants, making it exponentially harder for an adversary to trace your funds.

For example, if you mix in 5 rounds, an outside observer would need to analyze 5 separate transactions to attempt to link your original input to the final output. The more rounds you complete, the stronger your privacy guarantees.

However, more rounds also mean higher fees and longer wait times. A good balance is 3-5 rounds, depending on your threat model.

Using Multiple Mixdepths for Enhanced Obfuscation

JoinMarket supports mixdepths, which are essentially separate wallets within your JoinMarket wallet. Each mixdepth can have its own set of addresses and transaction history, making it harder to link your activities across different mixdepths.

For example, you can use one mixdepth for receiving funds from an exchange and another for spending mixed coins. This separation adds another layer of privacy.

Combining JoinMarket with Other Privacy Tools

To further enhance your privacy, consider combining JoinMarket mixing