🔄 BTC↔XMR Atomic Swaps

Exchange Bitcoin for Monero with zero trust required

⚡ What Are Atomic Swaps?

Atomic swaps let you exchange Bitcoin for Monero (or vice versa) without:

  • Centralized exchanges
  • KYC verification
  • Trusting anyone
  • Risk of exit scams

Either the swap completes fully or nothing happens. No middle ground. Pure cryptographic guarantee.

Why Atomic Swaps Matter

The Exchange Problem

  • Centralized exchanges: KYC destroys privacy
  • Instant exchangers: Often honeypots or scams
  • P2P trades: Require trust, risk of theft
  • Mixers: Being shut down and sanctioned

The Atomic Solution

Smart contracts on both chains ensure:

  • Both parties get paid or neither does
  • No custodian holds funds
  • No personal information exchanged
  • Completely decentralized

⚠️ Current Limitations

  • Technology is new and evolving
  • Limited liquidity
  • Higher fees than centralized exchanges
  • Requires technical knowledge
  • BTC→XMR works well, XMR→BTC is harder

How Atomic Swaps Work

Technical Overview

  1. Lock Phase: Both parties lock funds in smart contracts
  2. Proof Generation: Cryptographic proofs ensure fairness
  3. Claim/Refund: Either both claim or both refund after timeout
  4. No Middleman: Direct peer-to-peer transfer

The HTLC Magic

Hash Time-Locked Contracts (HTLCs) enable trustless swaps:

# Simplified concept
1. Alice creates secret S, shares hash H
2. Alice locks BTC: "Bob gets if he reveals S within 24h"
3. Bob locks XMR: "Alice gets if she reveals S within 12h"
4. Alice claims XMR, revealing S
5. Bob uses S to claim BTC
6. If timeout: Both get refunds

Atomic Swap Tools

1

UnstoppableSwap GUI (Easiest)

Best for beginners wanting BTC→XMR

Features:

  • User-friendly interface
  • Built on COMIT protocol
  • Tor integration
  • No registration required

Installation:

# Download from GitHub
https://github.com/UnstoppableSwap/unstoppableswap-gui/releases

# Verify signature (ALWAYS)
gpg --verify unstoppableswap-gui-*.asc

# Run
./unstoppableswap-gui

Basic Swap Process:

  1. Enter BTC amount to swap
  2. Get quote from available makers
  3. Accept best rate
  4. Send BTC to generated address
  5. Wait for confirmations
  6. Receive XMR automatically

⚠️ Always use Tor/VPN when running swap software

2

Farcaster (Advanced)

Full protocol implementation for power users

Features:

  • Complete swap protocol
  • Both BTC↔XMR directions
  • Command line interface
  • Maximum privacy options

Setup:

# Clone and build
git clone https://github.com/farcaster-project/farcaster-node
cd farcaster-node
cargo build --release

# Configure
cp config.toml.example config.toml
nano config.toml

# Set your Bitcoin and Monero nodes
[bitcoin]
url = "127.0.0.1:8332"
user = "your_rpc_user"
pass = "your_rpc_pass"

[monero]
url = "127.0.0.1:18081"

Running a Swap:

# As maker (provide liquidity)
./farcasterd --make-offer \
  --btc-amount 0.01 \
  --xmr-amount 0.5 \
  --timeout 3600

# As taker (accept offer)
./farcasterd --take-offer [OFFER_ID] \
  --btc-amount 0.01
3

COMIT Network Tools

The protocol powering many swap implementations

  • ASB (Automated Swap Backend): Run your own swap provider
  • CLI Tools: Command line swapping
  • Libraries: Build your own implementation

Run ASB (Become a Liquidity Provider):

# Download ASB
wget https://github.com/comit-network/xmr-btc-swap/releases/download/latest/asb

# Configure
./asb --help
./asb start \
  --bitcoin-wallet [WALLET] \
  --monero-wallet [WALLET] \
  --min-buy 0.001 \
  --max-buy 0.1 \
  --spread 0.02

Earn spread by providing liquidity!

Complete Swap Tutorial

Preparation

  1. Set up Bitcoin wallet (Electrum, Core)
  2. Set up Monero wallet (GUI, Feather)
  3. Run through Tor/VPN
  4. Have BTC ready (add extra for fees)
  5. Backup everything

Using UnstoppableSwap GUI

Step 1: Connect to Tor

# Start Tor
systemctl start tor

# Or use Tor Browser Bundle
# Configure UnstoppableSwap to use Tor proxy

Step 2: Start Swap

  1. Launch UnstoppableSwap
  2. Click "New Swap"
  3. Enter BTC amount (minimum usually 0.001)
  4. Review XMR amount and rate
  5. Click "Start Swap"

Step 3: Send Bitcoin

  • Copy deposit address (starts with bc1)
  • Send exact BTC amount
  • Wait for confirmations (usually 2)
  • DO NOT close application

Step 4: Automatic Execution

  • Software handles everything
  • Progress bar shows status
  • Takes 30-60 minutes typically
  • XMR appears in wallet automatically

💡 Swap Status Meanings

  • "Waiting for Bitcoin" - Send BTC
  • "Bitcoin Confirmed" - Smart contract active
  • "Executing Swap" - Cryptographic dance
  • "Claiming Monero" - Almost done
  • "Completed" - Check XMR wallet

Finding Liquidity

Swap Providers

  • UnstoppableSwap network
  • Seth for Privacy's ASB
  • Community providers
  • Check Matrix/IRC channels

Rate Discovery

  • Compare multiple providers
  • Expect 2-5% spread
  • Rates change with volatility
  • Smaller amounts = worse rates

Becoming a Maker

  • Run ASB to provide liquidity
  • Earn spread on swaps
  • Need both BTC and XMR
  • Higher risk, higher reward

Security Best Practices

🔐 Critical Security Rules

  1. Always verify signatures - Malicious software steals crypto
  2. Use Tor for everything - Hide swap activity
  3. Start with small amounts - Test the process
  4. Never share swap IDs - Links transactions
  5. Use fresh addresses - Don't reuse
  6. Wait for confirmations - Patience prevents problems

Common Attacks and Defenses

Time-Based Attacks

Attack: Delay transactions to exploit timeouts

Defense: Use recommended timelock periods, monitor actively

Fee Manipulation

Attack: Spam network to increase fees

Defense: Set appropriate fee limits, use RBF

Eclipse Attacks

Attack: Isolate your node from network

Defense: Run your own Bitcoin and Monero nodes

When Things Go Wrong

Swap Stuck

# Check status
./swap-cli status [SWAP_ID]

# Force refund if timeout
./swap-cli refund [SWAP_ID]

# Recovery always possible!

Connection Issues

  • Restart Tor
  • Try different provider
  • Check firewall rules
  • Verify node sync

Wrong Amount

  • Never send different amount
  • Include fees separately
  • If wrong: Wait for refund
  • Timeout = automatic refund

🔄 Refund Guarantee

Atomic swaps are atomic: Either both parties get paid or both get refunded. If anything goes wrong, you get your Bitcoin back after timeout (usually 24-72 hours).

Alternative Privacy Methods

Other Ways to Get Monero Privately

Method Privacy Difficulty Cost
Atomic Swaps Excellent Medium 2-5% spread
Bisq Exchange Good Medium 0.5-2% + deposit
Mining Monero Excellent Hard Electricity
LocalMonero Good Easy 5-10% premium
TradeOgre Medium Easy 0.2% fee
Cash by Mail Excellent Slow 5-15% premium

⚠️ LocalMonero announced shutdown in 2024. Be cautious of copycat sites.

The Future of Atomic Swaps

Coming Improvements

  • Better liquidity: More makers entering market
  • Mobile wallets: Swap from phone
  • Multi-asset: ETH↔XMR coming
  • Lightning integration: Instant swaps
  • Simplified UX: One-click swaps

Challenges Remaining

  • XMR→BTC direction still difficult
  • Requires running full nodes ideally
  • Limited by Bitcoin block times
  • Regulatory pressure increasing

True Financial Privacy

Atomic swaps represent the holy grail of cryptocurrency privacy: Converting traceable Bitcoin to untraceable Monero without trusting anyone.

Yes, it's more complex than using Binance. Yes, rates are worse. Yes, it takes longer.

But you keep your privacy. No KYC. No honeypots. No exit scams. Just pure cryptographic guarantee.

Every Bitcoin transaction is permanent evidence. Every Monero transaction is permanently private. Atomic swaps bridge that gap trustlessly.

Start Swapping

  1. Download UnstoppableSwap GUI
  2. Set up Tor connection
  3. Start with 0.001 BTC test
  4. Complete your first swap
  5. Never use KYC exchanges again

The tools exist. The liquidity is growing. Your privacy is waiting.

📚 Essential Resources