LORDS token bridge between Ethereum and Starknet.
- L1 token:
0x686f2404e77Ab0d9070a46cdfb0B7feCDD2318b0Etherscan - L1 bridge:
0x023A2aAc5d0fa69E3243994672822BA43E34E5C9Etherscan - L2 token:
0x124aeb495b947201f5fac96fd1138e326ad86195b98df6dec9009158a533b49Starkscan Voyager - L2 bridge:
0x7c76a71952ce3acd1f953fd2a3fda8564408b821ff367041c89f44526076633Starkscan Voyager
The bridge is built in a minimal fashion, without any external dependencies, immutable, non-upgradable. There is no support for message cancellation. It is built using Cairo v1.1.
For the high level overview of how Starknet L1 <> L2 messaging works, consult the official documentation.
When you want to bridge your $LORDS from Ethereum to Starknet, you need to call the deposit function of the L1 bridge with the amount of tokens to be bridged and the Starknet address to which the $LORDS will be added to. You'll also have to pay a small fee (at the time of writing set to 1 wei, but this is bound to change in the future) for the Starknet OS to process the message. The bridge calls transferFrom so you'll also have to approve it beforehand.
Once the Starknet sequencer processes the message, your L2 address will see the increased $LORDS balance. The L1 bridge acts as an escrow for the tokens, locking them in until (if ever) they are withdrawn from L2.
┌────────────────┐
│ L1 $LORDS │
│ token │
│ contract │
└────────────────┘
▲
│
│
transferFrom
│
┌─────────────┐ ┌───────┴───────┐
│ Ethereum │ │ │
│ $LORDS │────deposit─▶│ bridge.sol │────┐
│ owner │ │ │ │
└─────────────┘ └───────────────┘ │
│
sendMessageToL2
│
│
┌─────────────────┐ │
│ │ │
┌──│ StarkNet Core │◀─┘
│ │ │
│ └─────────────────┘
│
│
handle_deposit
│
│ ┌────────────────┐
│ │ │
└──▶│ bridge.cairo │
│ │
└────────────────┘
│
mint
│
▼
┌────────────────┐ ┌───────────┐
│ │ │ Starknet │
│ token.cairo ├──────────▶│ $LORDS │
│ │ │ owner │
└────────────────┘ └───────────┘
When moving $LORDS back from Starknet to Ethereum, call the initiate_withdrawal function on the L2 bridge with the L1 address and the amount of tokens to bridge back over to L1. After the sequencer processes the transaction and settles back to L1, you will be able to reclaim your $LORDS by calling withdraw on the L1 bridge contract. Note that you have to call withdraw with the same values as supplied to initiate_withdraw on L2, otherwise the L1 transaction will fail.
┌────────────────┐
│ │
│ token.cairo │
│ │
└────────────────┘
▲
│
burn
│
│
┌───────────┐ ┌────────────────┐
│ Starknet │ │ │
│ $LORDS │────initiate_withdrawal────▶│ bridge.cairo │───┐
│ owner │ │ │ │
└───────────┘ └────────────────┘ │
│
│
│
send_message_to_l1
│
│
┌─────────────────┐ │
│ │ │
┌─────▶│ Starknet Core │◀─┘
│ │ │
│ └─────────────────┘
│
consumeMessageFromL2
│
│
┌─────────┐ ┌───────────────┐
│Ethereum │ │ │
│ EOA │──withdraw───▶│ bridge.sol │────────┐
│ │ │ │ │
└─────────┘ └───────────────┘ │
transfer
│
▼
┌────────────────┐
│ L1 $LORDS │
│ token │
│ contract │
└────────────────┘