Contract: Burn Canonical Token (PeggedTokenBridgeV2)

Contract: Burn pegged tokens and unlock original token from cBridge

Implementation

The user can specify destination chain id when submitting burn transaction to PeggedTokenBridgeV2. The destination chain id can be original chain id which means the user will bring back his asset from OriginalTokenVault. The destination chain id could indicate another pegged chain where another PeggedTokenBridgeV2 is deployed and able to mint corresponding canonical token.

peggedTokenBridge!.burn(
     pegConfig.config.pegged_token.token.address, 
     value, 
     destinationChainId,
     address, 
     nonce)   

Request Parameters

Name	Type	Description
token	String	Pegged token address on the pegged chain
amount	UInt256	Burn amount
destinationChainId	UInt64	Destination Chain Id
withdraw_account	String	User's wallet address
nonce	UInt64	Current timestamp

If withdraw_account is a smart contract and the token you are sending is a wrapped native gas token on the destination chain, make sure the contract can receive native gas token by implementing fallback / receive functions.

TransferId Generation

When you submit on-chain burn transaction, you can also generate a transfer id for future reference. For example, it is used for getTransferStatus. It should be the same as transferId inside on-chain transaction log.

const burn_id = ethers.utils.solidityKeccak256(
     [
      "address",
      "address",
      "uint256", 
      "uint64",
      "address",
      "uint64", 
      "uint64",
      "address",
     ], 
     [
      "0x51d36e18e3d32d121a3cfe2f3e5771a6fd53274e", /// User's wallet address, 
      "0x37c92f7f65c40813b9404e9d031126550c39f8a8", /// selectedTokenAddress,
      "20000000000000000000", /// Burn amount in String 
      "...", /// Destination Chain Id
      "0x51d36e18e3d32d121a3cfe2f3e5771a6fd53274e", /// User's wallet address, 
      "....", /// Nonce
      "...", /// Pegged chain id
      "...", /// PeggedTokenBridgeV2 contract address
     ],
)

Please be aware that transfer id generation parameters are different between PeggedTokenBridge and PeggedTokenBridgeV2

Response

Since this function is an Ethereum on-chain transaction, the response is the corresponding transaction response.