LP-3004: Teleport Protocol - Cross-Chain Bridge with Remote Yield

Abstract

This LP defines the Teleport Protocol - a cross-chain bridge system that enables:

MPC-attested minting of collateral tokens (ETH, BTC, USDC)
Remote yield strategies for bridged assets on source chains
Integration with Liquid Protocol for self-repaying L* token loans
Separate token streams: collateral (deposits) and yield (debt repayment)

Teleport Protocol is the bridge layer; Liquid Protocol (LP-3003) is the lending layer. Together they enable self-repaying bridged asset loans.

Token Model

Token Type	Description	Minted By	Example
Collateral	Bridged asset (1:1 from source)	Teleporter.mintDeposit()	ETH
Synthetic	L* token (borrowed against collateral)	LiquidETH.borrow()	LETH
Yield	L* token (for debt repayment)	Teleporter.mintYield()	LETH

Key Insight: The Teleporter mints TWO different tokens:

collateralToken - ETH given to users who bridge
synthToken - LETH minted for yield, routed to LiquidVault to reduce debt

Motivation

Traditional bridges hold idle assets on source chains. Teleport Protocol enables:

Remote Yield: Bridged ETH earns yield via Lido, Aave, etc. on Ethereum/Base
Yield Ferrying: Yield from source chain is ferried back to Lux as LETH
Self-Repaying Loans: LETH yield automatically reduces user debt
Yield Gating: Only Liquid vault depositors earn yield

Protocol Architecture

┌─────────────────────────────────────────────────────────────────────────────────────────┐
│  TELEPORT PROTOCOL - NEW TOKEN MODEL                                                    │
├─────────────────────────────────────────────────────────────────────────────────────────┤
│                                                                                         │
│  EXTERNAL CHAINS (Ethereum/Base)                                                        │
│  ┌─────────────────────────────────────────────────────────────────────────────────┐   │
│  │ LiquidVault                                                                       │   │
│  │ - MPC-controlled ETH custody                                                      │   │
│  │ - Strategy allocation (Lido, Aave, Morpho, EigenLayer)                           │   │
│  │ - Yield harvesting                                                                │   │
│  │ - Withdrawal buffer                                                               │   │
│  └─────────────────────────────────────────────────────────────────────────────────┘   │
│         │ Deposit                    │ Yield                  │ Release                 │
└─────────┼────────────────────────────┼────────────────────────┼─────────────────────────┘
          │                            │                        │
          ▼ MPC: mintDeposit()         ▼ MPC: mintYield()       ▲ MPC: releaseETH()
┌─────────────────────────────────────────────────────────────────────────────────────────┐
│  LUX NETWORK                                                                            │
│                                                                                         │
│  ┌─────────────────────────────────────────────────────────────────────────────────┐   │
│  │ Teleporter                                                                        │   │
│  │ ├─ mintDeposit() → ETH (collateral) → User                                       │   │
│  │ └─ mintYield()  → LETH (synthetic) → LiquidETH vault → Reduces debt             │   │
│  └─────────────────────────────────────────────────────────────────────────────────┘   │
│                                                                                         │
│  USER FLOW:                                                                             │
│  ┌────────┐ deposit ┌─────────────┐ borrow ┌────────┐                                  │
│  │  ETH   │ ──────> │ LiquidETH   │ ─────> │  LETH  │                                  │
│  │(collat)│         │   Vault     │        │(synth) │                                  │
│  └────────┘         └─────────────┘        └────────┘                                  │
│                            ▲                                                            │
│                            │ onYieldReceived()                                          │
│                     LETH yield reduces debt                                             │
│                                                                                         │
└─────────────────────────────────────────────────────────────────────────────────────────┘

Specification

1. Teleporter (Lux)

Purpose: Burn/mint gateway with separate collateral and synthetic tokens

Location: contracts/liquid/teleport/Teleporter.sol

contract Teleporter is Ownable, AccessControl, ReentrancyGuard {
    bytes32 public constant MPC_ROLE = keccak256("MPC_ROLE");
    bytes32 public constant LIQUID_YIELD_ROLE = keccak256("LIQUID_YIELD_ROLE");

    /// @notice Collateral token (bridged ETH, USDC, etc.)
    IBridgedToken public immutable collateralToken;

    /// @notice Synthetic token (LETH, LUSD, etc.) - minted for yield only
    IBridgedToken public immutable synthToken;

    /// @notice Liquid vault for routing yield
    address public liquidVault;

    // Nonce tracking for replay protection
    mapping(uint256 => bool) public depositNonceUsed;
    mapping(uint256 => bool) public yieldNonceUsed;
    mapping(uint256 => bool) public withdrawNonceUsed;

    /// @notice Mint COLLATERAL to user for bridged deposit
    function mintDeposit(
        address recipient,
        uint256 amount,
        uint256 depositNonce,
        uint256 srcChainId,
        bytes calldata mpcSignature
    ) external onlyRole(MPC_ROLE) {
        require(!depositNonceUsed[depositNonce], "Nonce used");
        depositNonceUsed[depositNonce] = true;

        // Verify MPC signature
        _verifyMPCSignature(recipient, amount, depositNonce, srcChainId, mpcSignature);

        // Mint COLLATERAL (ETH) to recipient
        collateralToken.mint(recipient, amount);

        emit DepositMinted(recipient, amount, depositNonce, srcChainId);
    }

    /// @notice Mint SYNTHETIC to LiquidVault for yield/debt repayment
    function mintYield(
        uint256 amount,
        uint256 yieldNonce,
        uint256 srcChainId,
        bytes calldata mpcSignature
    ) external onlyRole(MPC_ROLE) {
        require(!yieldNonceUsed[yieldNonce], "Nonce used");
        yieldNonceUsed[yieldNonce] = true;
        require(liquidVault != address(0), "Vault not set");

        // Verify MPC signature
        _verifyMPCSignature(liquidVault, amount, yieldNonce, srcChainId, mpcSignature);

        // Mint SYNTHETIC (LETH) to vault for debt reduction
        synthToken.mint(liquidVault, amount);

        // Notify vault of yield
        ILiquidVault(liquidVault).onYieldReceived(amount, srcChainId);

        emit YieldMinted(liquidVault, amount, yieldNonce, srcChainId);
    }

    /// @notice Burn collateral for withdrawal to source chain
    function burn(
        uint256 amount,
        address dstRecipient,
        uint256 dstChainId
    ) external returns (uint256 withdrawNonce) {
        withdrawNonce = ++_withdrawNonce;

        // Burn COLLATERAL from user
        collateralToken.transferFrom(msg.sender, address(this), amount);
        collateralToken.burn(amount);

        emit BurnForWithdraw(msg.sender, dstRecipient, amount, withdrawNonce, dstChainId);
    }
}

Key Changes from Previous Model:

Two token types: collateralToken and synthToken
mintDeposit() → mints collateral (ETH) to user
mintYield() → mints synthetic (LETH) to vault for debt reduction
User receives ETH, NOT LETH, when bridging

2. TeleportVault (Base Contract)

Purpose: Abstract base for MPC-controlled custody vaults

Location: contracts/liquid/teleport/TeleportVault.sol

abstract contract TeleportVault is Ownable, AccessControl, ReentrancyGuard {
    bytes32 public constant MPC_ROLE = keccak256("MPC_ROLE");

    struct DepositProof {
        uint256 nonce;
        address luxRecipient;
        uint256 amount;
        uint256 timestamp;
        bool bridged;
    }

    uint256 public depositNonce;
    uint256 public withdrawNonce;
    mapping(uint256 => DepositProof) public deposits;

    /// @notice Record deposit for bridging
    function _recordDeposit(address luxRecipient, uint256 amount)
        internal returns (uint256 nonce);

    /// @notice Record release for withdrawal
    function _recordRelease(address recipient, uint256 amount, uint256 _withdrawNonce)
        internal;

    // Abstract
    function asset() external view virtual returns (address);
    function vaultBalance() external view virtual returns (uint256);
}

3. LiquidVault (External Chains)

Purpose: MPC-controlled ETH custody with yield strategy routing

Location: contracts/liquid/teleport/LiquidVault.sol

contract LiquidVault is TeleportVault {
    bytes32 public constant STRATEGY_ROLE = keccak256("STRATEGY_ROLE");

    struct Strategy {
        address adapter;           // IYieldStrategy implementation
        uint256 allocated;         // Amount in strategy
        uint256 lastHarvest;       // Last harvest timestamp
        bool active;               // Strategy active flag
    }

    Strategy[] public strategies;
    uint256 public minBufferBps = 1000;  // 10% minimum buffer

    /// @notice Deposit ETH and emit event for Lux mint
    function depositETH(address luxRecipient) external payable returns (uint256 nonce);

    /// @notice MPC: Allocate ETH to yield strategy
    function allocateToStrategy(
        uint256 strategyIndex,
        uint256 amount,
        bytes calldata mpcSignature
    ) external onlyRole(STRATEGY_ROLE);

    /// @notice MPC: Harvest yield from strategy
    function harvestYield(
        uint256 strategyIndex,
        bytes calldata mpcSignature
    ) external onlyRole(STRATEGY_ROLE) returns (uint256 harvested);

    /// @notice MPC: Release ETH for user withdrawal
    function releaseETH(
        address recipient,
        uint256 amount,
        uint256 _withdrawNonce
    ) external onlyRole(MPC_ROLE);
}

4. LiquidETH (Lux)

Purpose: Vault for ETH collateral with E-Mode 90% LTV, mints LETH on borrow

Location: contracts/liquid/teleport/LiquidETH.sol

contract LiquidETH is Ownable, AccessControl, ReentrancyGuard {
    // E-Mode Parameters
    uint256 public constant E_MODE_LTV = 9000;              // 90%
    uint256 public constant LIQUIDATION_THRESHOLD = 9400;   // 94%
    uint256 public constant LIQUIDATION_BONUS = 100;        // 1%

    /// @notice Collateral token (bridged ETH)
    IERC20 public immutable collateral;

    /// @notice Synthetic token (LETH - minted by vault)
    IBridgedToken public immutable synthetic;

    struct Position {
        uint256 collateral;  // ETH deposited
        uint256 debt;        // LETH borrowed
        uint256 lastUpdate;
    }
    mapping(address => Position) public positions;

    // Yield distribution
    uint256 public yieldIndex = 1e18;
    mapping(address => uint256) public userYieldIndex;

    /// @notice Deposit ETH collateral
    function deposit(uint256 amount) external;

    /// @notice Borrow LETH against ETH (mints LETH to user)
    function borrow(uint256 amount) external;

    /// @notice Repay LETH debt (burns LETH)
    function repay(uint256 amount) external;

    /// @notice Withdraw ETH collateral
    function withdraw(uint256 amount) external;

    /// @notice Receive yield from Teleporter (reduces debt pro-rata)
    function onYieldReceived(uint256 amount, uint256 srcChainId) external;

    /// @notice Liquidate undercollateralized position
    function liquidate(address user, uint256 debtToRepay) external;
}

5. LiquidYield (Lux)

Purpose: Optional yield processing helper

Location: contracts/liquid/teleport/LiquidYield.sol

contract LiquidYield is Ownable, AccessControl, ReentrancyGuard {
    IBridgedToken public immutable synthToken;
    ILiquidETH public liquidETH;

    /// @notice Receive yield from Teleporter and route to vault
    function onYieldReceived(uint256 amount, uint256 srcChainId) external;

    /// @notice Process any pending yield
    function process() external;
}

Message Flows

A) Bridge In (User receives ETH collateral)

User deposits ETH on Ethereum/Base
    │
    ▼
LiquidVault.depositETH(luxRecipient) → DepositRecorded event
    │
    ▼ MPC attestation
Teleporter.mintDeposit(recipient, amount, nonce, chainId, sig)
    │
    ▼
User receives ETH (collateral) on Lux
    │
    ▼ Optional: User deposits into LiquidETH to borrow LETH
LiquidETH.deposit(ethAmount)
LiquidETH.borrow(lethAmount)  // Up to 90% LTV
    │
    ▼
User has LETH (synthetic) to use in DeFi

B) Yield Flow (Automatic debt repayment)

MPC calls LiquidVault.harvestYield(strategyIndex, sig)
    │
    ▼
Yield realized in LiquidVault buffer
    │
    ▼ MPC attestation
Teleporter.mintYield(amount, yieldNonce, chainId, sig)
    │
    ▼
LETH minted to LiquidETH vault
    │
    ▼
LiquidETH.onYieldReceived(amount, chainId)
    │
    ▼
yieldIndex updated, all borrower debts reduced pro-rata
LETH is burned (debt reduction = token burn)

C) Bridge Out (Withdraw ETH)

User calls LiquidETH.repay(lethAmount)  // Burns LETH
    │
    ▼
User calls LiquidETH.withdraw(ethAmount)  // Get ETH collateral back
    │
    ▼
User calls Teleporter.burn(ethAmount, dstRecipient, dstChainId)
    │
    ▼
BurnForWithdraw event emitted
    │
    ▼ MPC monitors
LiquidVault.releaseETH(recipient, amount, withdrawNonce)
    │
    ▼
User receives ETH on source chain

Yield Strategies

Location: contracts/yield/strategies/

Strategy	Protocol	APY Range	Risk
`LidoStrategy.sol`	Lido	3-5%	Low
`RocketPoolStrategy.sol`	Rocket Pool	3-4%	Low
`AaveV3Strategy.sol`	Aave V3	2-4%	Low
`CompoundV3Strategy.sol`	Compound V3	2-3%	Low
`MorphoStrategy.sol`	Morpho	3-5%	Medium
`EigenLayerStrategy.sol`	EigenLayer	4-8%	Medium
`ConvexStrategy.sol`	Convex/Curve	5-15%	Medium
`YearnV3Strategy.sol`	Yearn V3	3-8%	Medium

IYieldStrategy Interface

interface IYieldStrategy {
    function deposit(uint256 amount) external payable returns (uint256 shares);
    function withdraw(uint256 shares) external returns (uint256 assets);
    function harvest() external returns (uint256 harvested);
    function totalAssets() external view returns (uint256);
    function currentAPY() external view returns (uint256);
    function isActive() external view returns (bool);
    function name() external view returns (string memory);
    function vault() external view returns (address);
}

Roles

Role	Responsibilities
MPC Attestor	Signs remote-chain event attestations
MPC Operator	Executes LiquidVault operations
Keeper	Calls yield processing functions
Admin	Sets params, caps, pauses

Core Invariants

Two Token Streams: Deposits mint collateral; yield mints synthetic
Yield Gating: Only LiquidETH depositors benefit from yield
Replay Safety: Unique nonces per operation type
Solvency: Buffer + unwind can honor withdrawals

Safety Controls

Market pause (borrow/withdraw separately)
Strategy allowlist + caps
Slippage limits on swaps
Buffer floor on LiquidVault
Global caps for launch

Reference Implementation

Contract	Location	Lines
TeleportVault	`contracts/liquid/teleport/TeleportVault.sol`	~250
LiquidVault	`contracts/liquid/teleport/LiquidVault.sol`	~400
Teleporter	`contracts/liquid/teleport/Teleporter.sol`	~400
LiquidETH	`contracts/liquid/teleport/LiquidETH.sol`	~500
LiquidYield	`contracts/liquid/teleport/LiquidYield.sol`	~150
IYieldStrategy	`contracts/yield/IYieldStrategy.sol`	~175
Strategies	`contracts/yield/strategies/*.sol`	~5000

LP	Title	Relationship
LP-3001	Teleport Bridge MPC	Base bridge protocol
LP-3003	Liquid Protocol	Lending layer
LP-3810	Teleport Token Standard	Token interface
LP-6022	Warp Messaging 2.0	Cross-chain

Rationale

The cross-chain teleport design uses a hub-and-spoke model because:

Reduces complexity compared to fully meshed connections
Lux Network acts as the liquidity hub
MPC signatures provide decentralized security
Warp Messaging provides native interoperability

Backwards Compatibility

This LP extends LP-3001 (Teleport Bridge MPC) and is backwards compatible with existing bridge deployments.

Security Considerations

Key security measures:

MPC threshold signatures prevent single points of failure
Rate limiting protects against flash loan attacks
Timelocks on large withdrawals
Oracle manipulation resistance through multi-source price feeds

Teleport Protocol - Cross-Chain Bridge with Remote Yield