heady_wook on Nostr: Implementing a decentralized version of Samourai Wallet’s Whirlpool coin join ...
Implementing a decentralized version of Samourai Wallet’s Whirlpool coin join protocol would require redesigning its existing coordinator-based architecture to remove reliance on a central server. Here’s a high-level approach:
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1. Understanding Whirlpool's Current Design
Whirlpool currently relies on a coordinator to facilitate the coin join process.
Clients register inputs, the coordinator builds the transaction, and participants sign it.
The coordinator doesn’t take custody of funds but still knows the transaction structure before broadcasting.
2. Key Challenges for Decentralization
Removing the coordinator without reducing efficiency.
Ensuring Sybil resistance to prevent DoS or manipulation.
Maintaining privacy while coordinating transactions.
Minimizing reliance on a single blockchain explorer or external services.
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3. Decentralized Whirlpool: Potential Design Approaches
To decentralize Whirlpool, we could leverage one or a combination of the following:
A. Peer-to-Peer (P2P) Coordination Using Tor/I2P
Use a DHT (Distributed Hash Table) for peer discovery.
Clients initiate coin joins directly in a P2P fashion.
Nodes use Tor or I2P for anonymity.
B. Federated or Multiparty Coordination
Instead of a single server, use multiple semi-trusted facilitators.
Shamir’s Secret Sharing could be used to prevent any single entity from knowing the full transaction structure.
A threshold cryptographic scheme could allow transactions to be constructed collectively.
C. Bitcoin Script & Covenant Approaches
Use vault-like smart contracts (e.g., OP_CTV, OP_CHECKSIGFROMSTACK) to enforce coin join conditions.
Create "CoinJoin Pools" where users deposit funds and can only withdraw through pre-agreed anonymity conditions.
D. Lightning Network for Pre-Mixing
Before on-chain settlement, users could mix UTXOs off-chain via the Lightning Network.
This avoids large on-chain transaction fees and improves speed.
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4. Implementation Steps
1. Peer Discovery Layer
Use a decentralized network (DHT, Nostr relays, or LN-based signaling).
Implement a reputation system to mitigate Sybil attacks.
2. Decentralized Input Coordination
Use a Zero-Knowledge proof system (e.g., zkSNARKs) to verify valid inputs without revealing them.
Alternatively, Ring Signatures or Threshold Signatures could be used.
3. Transaction Construction Without a Coordinator
Each participant signs their input separately.
Use secure multiparty computation (MPC) to build the final transaction.
4. Broadcast & Finalization
The final transaction is either broadcast by multiple peers simultaneously or via a privacy-preserving relay (e.g., FIBRE, Tor).
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5. Potential Risks & Mitigation
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6. Conclusion
A fully decentralized Whirlpool would likely rely on P2P coordination, zero-knowledge proofs, and multiparty computation to remove the need for a trusted coordinator while preserving privacy and efficiency. It would be a complex but highly valuable upgrade to Bitcoin's privacy ecosystem.
---
1. Understanding Whirlpool's Current Design
Whirlpool currently relies on a coordinator to facilitate the coin join process.
Clients register inputs, the coordinator builds the transaction, and participants sign it.
The coordinator doesn’t take custody of funds but still knows the transaction structure before broadcasting.
2. Key Challenges for Decentralization
Removing the coordinator without reducing efficiency.
Ensuring Sybil resistance to prevent DoS or manipulation.
Maintaining privacy while coordinating transactions.
Minimizing reliance on a single blockchain explorer or external services.
---
3. Decentralized Whirlpool: Potential Design Approaches
To decentralize Whirlpool, we could leverage one or a combination of the following:
A. Peer-to-Peer (P2P) Coordination Using Tor/I2P
Use a DHT (Distributed Hash Table) for peer discovery.
Clients initiate coin joins directly in a P2P fashion.
Nodes use Tor or I2P for anonymity.
B. Federated or Multiparty Coordination
Instead of a single server, use multiple semi-trusted facilitators.
Shamir’s Secret Sharing could be used to prevent any single entity from knowing the full transaction structure.
A threshold cryptographic scheme could allow transactions to be constructed collectively.
C. Bitcoin Script & Covenant Approaches
Use vault-like smart contracts (e.g., OP_CTV, OP_CHECKSIGFROMSTACK) to enforce coin join conditions.
Create "CoinJoin Pools" where users deposit funds and can only withdraw through pre-agreed anonymity conditions.
D. Lightning Network for Pre-Mixing
Before on-chain settlement, users could mix UTXOs off-chain via the Lightning Network.
This avoids large on-chain transaction fees and improves speed.
---
4. Implementation Steps
1. Peer Discovery Layer
Use a decentralized network (DHT, Nostr relays, or LN-based signaling).
Implement a reputation system to mitigate Sybil attacks.
2. Decentralized Input Coordination
Use a Zero-Knowledge proof system (e.g., zkSNARKs) to verify valid inputs without revealing them.
Alternatively, Ring Signatures or Threshold Signatures could be used.
3. Transaction Construction Without a Coordinator
Each participant signs their input separately.
Use secure multiparty computation (MPC) to build the final transaction.
4. Broadcast & Finalization
The final transaction is either broadcast by multiple peers simultaneously or via a privacy-preserving relay (e.g., FIBRE, Tor).
---
5. Potential Risks & Mitigation
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6. Conclusion
A fully decentralized Whirlpool would likely rely on P2P coordination, zero-knowledge proofs, and multiparty computation to remove the need for a trusted coordinator while preserving privacy and efficiency. It would be a complex but highly valuable upgrade to Bitcoin's privacy ecosystem.