2.7 KiB
Concepts
ERC20 token <> sdk.Coin Conversion
x/evmutil facilitates moving assets between Kava's EVM and Cosmos co-chains. This must be handled differently depending on which co-chain to which the asset it native. The messages controlling these flows involve two accounts:
- The initiator who sends coins from their co-chain
- The receiver who receives coins on the other co-chain
When converting assets from the EVM to the Cosmos co-chain, the initiator is an 0x EVM address and the receiver is a kava1 Bech32 address.
When converting assets from the Cosmos co-chain to the EVM, the initiator is a kava1 Bech32 address and the receiver is an 0x EVM address.
Cosmos-Native Assets
sdk.Coins native to the Cosmos co-chain can be converted to an ERC-20 representing the coin in the EVM. This works by transferring the coin from the initiator to x/evmutil's module account and then minting an ERC-20 token to the receiver. Converting back, the initiator's ERC-20 representation of the coin is burned and the original Cosmos-native asset is transferred to the receiver.
Cosmos-native asset conversion is done through the use of the MsgConvertCosmosCoinToERC20 & MsgConvertCosmosCoinFromERC20 messages (see Messages).
Only Cosmos co-chain denominations that are in the AllowedCosmosDenoms param (see Params) can be converted via these messages.
AllowedCosmosDenoms can be altered through governance.
The ERC20 contracts are deployed and managed by x/evmutil. The contract is deployed on first convert of the coin. Once deployed, the addresses of the contracts can be queried via the DeployedCosmosCoinContracts query (deployed_cosmos_coin_contracts endpoint).
If a denom is removed from the AllowedCosmosDenoms param, existing ERC20 tokens can be converted back to the underlying sdk.Coin via MsgConvertCosmosCoinFromERC20, but no conversions from sdk.Coin -> ERC via MsgConvertCosmosCoinToERC20 are allowed.
EVM-Native Assets
ERC-20 tokens native to the EVM can be converted into an sdk.Coin in the Cosmos ecosystem. This works by transferring the tokens to x/evmutil's module account and then minting an sdk.Coin to the receiver. Converting back is the inverse: the sdk.Coin of the initiator is burned and the original ERC-20 tokens that were locked into the module account are transferred back to the receiver.
EVM-native asset conversion is done through the use of the MsgConvertERC20ToCoin & MsgConvertCoinToERC20 messages (see Messages).
Only ERC20 contract address that are in the EnabledConversionPairs param (see Params) can be converted via these messages.
EnabledConversionPairs can be altered through governance.