# 🌉 FHEBridge

## Quick Info:

* 🧱 [Mind Network FHEBridge Dapp](https://fhebridge.mindnetwork.xyz/)
* 📖 FHEBridge Guide: [Transfer](/minddocs/product/fhebridge/fhebridge-guide-transfer.md), [Bridge](/minddocs/product/fhebridge/fhebridge-guide-bridge.md), [Manage](/minddocs/product/fhebridge/fhebridge-guide-manage.md)
* 📜 [Stealth Address Protocol Contracts](https://github.com/mind-network/mind-sap-contracts)
* 📚 Research Materials:
  * [Arxiv](https://arxiv.org/abs/2312.10698)
  * [Ethereum Research](https://ethresear.ch/t/fhe-dksap-fully-homomorphic-encryption-based-dual-key-stealth-address-protocol/16213)
  * [DevConnect Talk](https://app.streameth.org/devconnect/epf_day/session/fhedksap)
* 🎥 [YouTube Walkthrough](https://www.youtube.com/watch?v=XjsNW0GX76w)
* 🛠️ [SDK + Demos](https://github.com/mind-network/mind-sap-sdk-demo)
* 📋 [Audit Reports](https://github.com/mind-network/mind-sap-contracts/tree/main/audit)

## What is FHEBridge 

FHE Bridge is a cross-chain communication bridge developed in collaboration with Chainlink, designed to securely transmit data across different blockchains. The core technologies underpinning FHE Bridge are the Cross-Chain Interoperability Protocol (CCIP) and the Stealth Address Protocol (SAP).

## **What is Stealth Address Protocol (SAP)** 

The Stealth Address (SA) prevents the public association of a blockchain transaction's output with a recipient's wallet address, effectively concealing the actual destination address of the transaction. As Vitalik highlighted the practical and privacy-preserving implementation of SA in the application layer of programmable blockchains such as Ethereum, we propose a SA protocol with Fully Homomorphic Encryption (FHE) to prevent quantum computing attacks based on Learning with Error (LWE) security assumption. 

While the original proposal of SA builds on the dual-key, our approach, FHE-DKSAP, can help the receiver outsource the computation of checking the entire chain for stealth addresses containing assets without revealing his view key, and prevent quantum computing attacks based on the lattice cryptographic construction that relies on far simpler mathematics than elliptic curve.

<figure><img src="/files/wISsFUEqrg90zvendukd" alt=""><figcaption></figcaption></figure>

### **What Can the FHE Bridge Do?** <a href="#what-can-the-fhe-bridge-do" id="what-can-the-fhe-bridge-do"></a>

* **Bank Chain to Public Chain**: Securely bridge traditional finance systems to public blockchains, fostering seamless transactions while safeguarding sensitive financial data.
* **CBDC Chain to Public Chain**: Facilitate the integration of central bank digital currencies into the world of public blockchains, ensuring the privacy and security of digital assets.
* **Public Chain to Public Chain**: Foster secure cross-chain interactions between different public blockchains, expanding the horizons of decentralized finance (DeFi) and enabling the free flow of digital assets.

## Supported Networks&#x20;

1. **Ethereum:** The leading blockchain network known for its extensive ecosystem and security
2. **Polygon:** A layer-2 scaling solution offering fast transactions and low fees while maintaining compatibility with Ethereum.&#x20;
3. **Arbitrum:** A layer-2 scaling solution focusing on optimized transactions, with enhanced throughput and reduced costs.&#x20;
4. **BNBChain**: A layer-2 scaling solution focusing on optimized transactions, with enhanced throughput and reduced costs.&#x20;

## Supported Tokens&#x20;

* **ETH:** The native cryptocurrency of the Ethereum & Arbitrum network.&#x20;
* **MATIC:** The native token of the Polygon network.&#x20;
* **USDC:** A stablecoin pegged to the U.S. Dollar, available on all three networks.
* **FHE**: Mind Network Token

## **How to Use the FHE Bridge**

Users can utilize the FHEBridge to transfer assets across chains seamlessly, check [FHEBridge User Guide](/minddocs/product/fhebridge/fhebridge-guide-transfer.md):

* **🔄 Initiate a Bridge Transaction:** Select the asset and network, then submit the transaction.
* **✅ Confirm & Process:** Transactions take approximately 20 minutes to complete due to CCIP’s velocity. Please be patient.
* **📜 Track Transaction History:** Users can review past transactions via the History section and download records if needed.


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