Cross-Chain Bridge

USDSM can be bridged across supported chains using LayerZero V2 OFT (Omnichain Fungible Token). Transfers use a burn-and-mint model — tokens are burned on the source chain and minted on the destination chain. Total supply is always conserved.

Supported Chains

Chain	USDSM Token	OFT Adapter	MinterBurner	LZ Endpoint ID
Ethereum	0x399B29975CBE313C56269cD5097F5AE097Fa2741	0x0aFa4BE6fA5ebAf5fFEe3AB9F88EAA3e16c37aDE	0x6A02e153bCbF9e6BE45C0b49F7F0ABc82859ebD5	30101
Base	0x26C358F7c5fEdB20a6ddEf108cD91Efb6B8Da0Cb	0x1053BaF5964b82859F6aa140ED2C02f2975075eB	0x6bDE51212203aE5d592Cc5180DA2ABBd41c922dE	30184
Arbitrum	0x26C358F7c5fEdB20a6ddEf108cD91Efb6B8Da0Cb	0x1053BaF5964b82859F6aa140ED2C02f2975075eB	0x6bDE51212203aE5d592Cc5180DA2ABBd41c922dE	30110
Etherlink	0x6bDE51212203aE5d592Cc5180DA2ABBd41c922dE	0xe7F117F87fa650350c3E363ca2C644951d273d1F	0x28DA1dFaF5DCa1AF226a2e56B834E8Ec3C495C5A	30292

Architecture

Each chain has three contracts:

• USDSM — The ERC-20 token (TransparentUpgradeableProxy)
• USDSMMintBurnOFTAdapter — LayerZero V2 OFT adapter that handles cross-chain send/receive
• USDSMMinterBurner — Intermediary that translates between LayerZero's standard interface and USDSM's mint/burn signatures

How a bridge transfer works

Source Chain                          Destination Chain
────────────                          ─────────────────
1. User approves MinterBurner
2. User calls adapter.send()
3. MinterBurner burns USDSM
4. LayerZero sends message ──────────► 5. LayerZero delivers message
                                       6. MinterBurner mints USDSM to user

Security

• 2/2 DVN verification — Every message is verified by two independent Decentralized Verifier Networks (LZ Labs + Horizen) before delivery
• Explicit library pinning — Send and receive message libraries are pinned to specific versions per pathway
• Enforced gas options — Minimum 120,000 gas enforced for lzReceive on all pathways

Important: Approval Target

WARNING

When bridging USDSM, you must approve the MinterBurner contract — not the OFT Adapter. This is because USDSM uses a non-standard mint/burn signature with a deduplication ID, and the MinterBurner handles the transferFrom during the burn flow.

Chain	Approve this address (MinterBurner)
Ethereum	0x6A02e153bCbF9e6BE45C0b49F7F0ABc82859ebD5
Base	0x6bDE51212203aE5d592Cc5180DA2ABBd41c922dE
Arbitrum	0x6bDE51212203aE5d592Cc5180DA2ABBd41c922dE
Etherlink	0x28DA1dFaF5DCa1AF226a2e56B834E8Ec3C495C5A

This applies to both direct user interactions and partner integrations (e.g., bridge aggregators like LiFi/Jumper).