Privacy Mixer

Privacy Mixer

Multi-layer privacy protocol using shielded pools, stealth addresses, and confidential transactions. Monero-level privacy for Ethereum.

Architecture

Shielded Pool System

Macro uses a continuous shielded balance system, not traditional deposit/withdraw mixing.

How it works:

• Assets move into encrypted on-chain balances (shielded pool)

• All transfers within pool are confidential (hidden amounts, addresses, transactions)

• Withdrawals use stealth addresses via decentralized relayers

• No public transaction graph

Key components:

Note-based system - Each balance is an encrypted note with hidden amount and owner

Merkle tree - All notes stored in on-chain Merkle tree

Nullifiers - Spent notes marked to prevent double-spending

ZK-SNARKs - Prove valid transactions without revealing details

Confidential Transactions

Amounts hidden using Pedersen commitments and bulletproof range proofs.

Transaction privacy:

• Sender amount: Hidden

• Receiver amount: Hidden

• Transaction balance: Verified cryptographically without revealing values

• Range proofs: Confirm positive amounts without disclosure

What observers see:

On-chain view:
- Commitment A → Commitment B
- Range proof: ✅ Valid
- Zero amounts visible

Your view:
- Sent: 2.5 ETH
- To: [stealth address]

Stealth Addresses

One-time recipient addresses derived from meta-address. Sender cannot track, only receiver can detect and claim.

Protocol (ERC-5564):

1. Receiver publishes stealth meta-address

2. Sender derives ephemeral one-time address

3. Funds sent to one-time address

4. Receiver scans chain, detects payment, derives private key

5. No public link between meta-address and one-time address

Decentralized Relayer Network

Relayers submit withdrawals to prevent IP/timing correlation.

Architecture:

• 100+ independent relayers (run by $MACRO stakers)

• Onion routing: Request passes through 3 relayers (entry → middle → exit)

• Tor integration for IP protection

• Batched submissions (10-50 withdrawals bundled)

• Fee paid from shielded balance (no external payment trail)

Privacy guarantees:

• No single relayer knows origin, destination, and amount

• Exit relayer submits but cannot correlate with requester

• Randomized delays prevent timing analysis

Multi-Hop Routing

For enhanced privacy, route through multiple pools across chains.

Enhanced unshield:

User balance (Ethereum Pool) → 
Arbitrum Pool (cross-chain bridge) → 
Polygon Pool → 
Unshield via relayer → 
Stealth address

Each hop adds entropy and breaks correlation.

How to Use

Shield Assets

Access: Wallet Panel → Privacy Layer

Select asset and amount:

• Supported: ETH, USDC, USDT, DAI, WBTC

• No minimum (confidential amounts)

• Fee: 0.1%

Transaction:

Funds move to shielded pool. Balance encrypted on-chain, visible only to you.

Manage Shielded Balance

Available actions:

• Send - Transfer to stealth addresses (private)

• Swap - Exchange assets within pool (confidential)

• Unshield - Exit to public address

Unshield Options

Standard (2-5 min):

• Direct unshield

• Good privacy

• Fee: 0.3%

Enhanced (30-60 min):

• Multi-hop routing (3 pools)

• Decentralized relayer submission

• Stealth address

• Fee: 0.5%

Ultra (1-6 hours):

• Cross-chain multi-hop

• 5+ relayer hops

• Batched with others

• Random delays

• Fee: 0.8%

Claim from Stealth Address

Final step: Claim funds from stealth address to your destination.

Best practices:

• Use fresh address

• Wait before exchange deposits

• Enable VPN

• Maintain operational security

Technical Details

Smart Contract Architecture

contract MacroShieldedPool {
  mapping(bytes32 => bool) public nullifiers;
  uint256 public merkleRoot;
  
  function shield(uint256 amount) external;
  function transact(bytes zkProof, bytes publicInputs) external;
  function unshield(bytes zkProof, address recipient) external;
}

ZK Proof System

Inputs:

• Public: Nullifiers, commitments, Merkle root

• Private: Amounts, addresses, keys

Proof: Valid transaction with balanced inputs/outputs

Verification: On-chain verification (~300k gas)

Cryptographic Primitives

Pedersen commitments:

C = amount * G + blinding * H

Range proofs: Bulletproofs (~700 bytes)

Stealth addresses: Elliptic curve Diffie-Hellman

ZK circuits: Groth16 SNARKs

Security

Threat Model

Protected against:

• Chain analysis (Chainalysis, Elliptic)

• Timing analysis

• Amount correlation

• IP tracking

• Graph analysis

• Statistical attacks

Not protected against:

• User operational errors

• Compromised devices

• Legal key disclosure

Audits

• Trail of Bits (smart contracts)

• OpenZeppelin (smart contracts)

• ABDK (ZK circuits)

• Sigma Prime (ZK circuits)

Bug bounty: $500k

Privacy Comparison

Feature	Tornado Cash	Aztec	Monero	Macro
Shielded balances	❌	✅	✅	✅
Confidential amounts	❌	✅	✅	✅
Stealth addresses	❌	❌	✅	✅
Decentralized relayers	❌	❌	N/A	✅
Multi-chain routing	❌	Limited	❌	✅
Browser integration	❌	❌	❌	✅

Fees

• Shield: 0.1%

• Internal transfer: 0.05%

• Unshield (standard): 0.3%

• Unshield (enhanced): 0.5%

• Unshield (ultra): 0.8%

Plus gas fees (200k-350k gas depending on operation).

Fee distribution:

• 60% to relayer operators

• 20% to liquidity providers

• 20% to protocol treasury

Legal Considerations

Privacy tools are legal in most jurisdictions. Users responsible for compliance with local laws. Some exchanges flag shielded deposits.

Macro's position: Privacy is a right. The mixer is designed for legitimate financial privacy, not illegal activity.

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One line: Shielded pool with confidential transactions, stealth addresses, and decentralized relayers. Monero-level privacy for Ethereum.