# Transactions

This section defines the `sdk.Msg` concrete types that result in the state transitions defined on the previous section.

### `MsgEthereumTx` <a href="#msgethereumtx" id="msgethereumtx"></a>

An EVM state transition can be achieved by using the `MsgEthereumTx`. This message encapsulates an Ethereum transaction data (`TxData`) as a `sdk.Msg`.&#x20;

It contains the necessary transaction data fields. Note, that the `MsgEthereumTx` implements both the [`sdk.Msg` ](https://github.com/cosmos/cosmos-sdk/blob/v0.39.2/types/tx_msg.go#L7-L29)and [`sdk.Tx` ](https://github.com/cosmos/cosmos-sdk/blob/v0.39.2/types/tx_msg.go#L33-L41)interfaces. Normally, SDK messages only implement the former, while the latter is a group of messages bundled together.

```go
type MsgEthereumTx struct {
 // inner transaction data
 Data *types.Any `protobuf:"bytes,1,opt,name=data,proto3" json:"data,omitempty"`
 // DEPRECATED: encoded storage size of the transaction
 Size_ float64 `protobuf:"fixed64,2,opt,name=size,proto3" json:"-"`
 // transaction hash in hex format
 Hash string `protobuf:"bytes,3,opt,name=hash,proto3" json:"hash,omitempty" rlp:"-"`
 // ethereum signer address in hex format. This address value is checked
 // against the address derived from the signature (V, R, S) using the
 // secp256k1 elliptic curve
 From string `protobuf:"bytes,4,opt,name=from,proto3" json:"from,omitempty"`
}
```

This message field validation is expected to fail if:

* `From` field is defined and the address is invalid
* `TxData` stateless validation fails

The transaction execution is expected to fail if:

* Any of the custom `AnteHandler` Ethereum decorators checks fail:
  * Minimum gas amount requirements for transaction
  * Tx sender account doesn't exist or hasn't enough balance for fees
  * Account sequence doesn't match the transaction `Data.AccountNonce`
  * Message signature verification fails
* EVM contract creation (i.e `evm.Create`) fails, or `evm.Call` fails

#### Conversion <a href="#conversion" id="conversion"></a>

The `MsgEthreumTx` can be converted to the go-ethereum `Transaction` and `Message` types in order to create and call evm contracts.

```go
// AsTransaction creates an Ethereum Transaction type from the msg fields
func (msg MsgEthereumTx) AsTransaction() *ethtypes.Transaction {
 txData, err := UnpackTxData(msg.Data)
 if err != nil {
  return nil
 }

 return ethtypes.NewTx(txData.AsEthereumData())
}

// AsMessage returns the transaction as a core.Message.
func (tx *Transaction) AsMessage(s Signer, baseFee *big.Int) (Message, error) {
 msg := Message{
  nonce:      tx.Nonce(),
  gasLimit:   tx.Gas(),
  gasPrice:   new(big.Int).Set(tx.GasPrice()),
  gasFeeCap:  new(big.Int).Set(tx.GasFeeCap()),
  gasTipCap:  new(big.Int).Set(tx.GasTipCap()),
  to:         tx.To(),
  amount:     tx.Value(),
  data:       tx.Data(),
  accessList: tx.AccessList(),
  isFake:     false,
 }
 // If baseFee provided, set gasPrice to effectiveGasPrice.
 if baseFee != nil {
  msg.gasPrice = math.BigMin(msg.gasPrice.Add(msg.gasTipCap, baseFee), msg.gasFeeCap)
 }
 var err error
 msg.from, err = Sender(s, tx)
 return msg, err
}
```

#### Signing <a href="#signing" id="signing"></a>

In order for the signature verification to be valid, the `TxData` must contain the `v | r | s` values from the `Signer`. Sign calculates a secp256k1 ECDSA signature and signs the transaction. It takes a keyring signer and the chainID to sign an Ethereum transaction according to EIP155 standard.&#x20;

This method mutates the transaction as it populates the V, R, S fields of the Transaction's Signature. The function will fail if the sender address is not defined for the msg or if the sender is not registered on the keyring.

```go
// Sign calculates a secp256k1 ECDSA signature and signs the transaction. It
// takes a keyring signer and the chainID to sign an Ethereum transaction according to
// EIP155 standard.
// This method mutates the transaction as it populates the V, R, S
// fields of the Transaction's Signature.
// The function will fail if the sender address is not defined for the msg or if
// the sender is not registered on the keyring
func (msg *MsgEthereumTx) Sign(ethSigner ethtypes.Signer, keyringSigner keyring.Signer) error {
 from := msg.GetFrom()
 if from.Empty() {
  return fmt.Errorf("sender address not defined for message")
 }

 tx := msg.AsTransaction()
 txHash := ethSigner.Hash(tx)

 sig, _, err := keyringSigner.SignByAddress(from, txHash.Bytes())
 if err != nil {
  return err
 }

 tx, err = tx.WithSignature(ethSigner, sig)
 if err != nil {
  return err
 }

 msg.FromEthereumTx(tx)
 return nil
}
```

### TxData <a href="#txdata" id="txdata"></a>

The `MsgEthereumTx` supports the 3 valid Ethereum transaction data types from go-ethereum: `LegacyTx`, `AccessListTx` and `DynamicFeeTx`. These types are defined as protobuf messages and packed into a `proto.Any` interface type in the `MsgEthereumTx` field.

* `LegacyTx`: [EIP-155 ](https://github.com/ethereum/EIPs/blob/master/EIPS/eip-155.md)transaction type
* `DynamicFeeTx`: [EIP-1559 ](https://eips.ethereum.org/EIPS/eip-1559)transaction type. Enabled by London hard fork block
* `AccessListTx`: [EIP-2930 ](https://eips.ethereum.org/EIPS/eip-2930)transaction type. Enabled by Berlin hard fork block

#### `LegacyTx` <a href="#legacytx" id="legacytx"></a>

The transaction data of regular Ethereum transactions.

```go
type LegacyTx struct {
 // nonce corresponds to the account nonce (transaction sequence).
 Nonce uint64 `protobuf:"varint,1,opt,name=nonce,proto3" json:"nonce,omitempty"`
 // gas price defines the value for each gas unit
 GasPrice *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,2,opt,name=gas_price,json=gasPrice,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"gas_price,omitempty"`
 // gas defines the gas limit defined for the transaction.
 GasLimit uint64 `protobuf:"varint,3,opt,name=gas,proto3" json:"gas,omitempty"`
 // hex formatted address of the recipient
 To string `protobuf:"bytes,4,opt,name=to,proto3" json:"to,omitempty"`
 // value defines the unsigned integer value of the transaction amount.
 Amount *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,5,opt,name=value,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"value,omitempty"`
 // input defines the data payload bytes of the transaction.
 Data []byte `protobuf:"bytes,6,opt,name=data,proto3" json:"data,omitempty"`
 // v defines the signature value
 V []byte `protobuf:"bytes,7,opt,name=v,proto3" json:"v,omitempty"`
 // r defines the signature value
 R []byte `protobuf:"bytes,8,opt,name=r,proto3" json:"r,omitempty"`
 // s define the signature value
 S []byte `protobuf:"bytes,9,opt,name=s,proto3" json:"s,omitempty"`
}
```

This message field validation is expected to fail if:

* `GasPrice` is invalid (`nil` , negaitve or out of int256 bound)
* `Fee` (gasprice \* gaslimit) is invalid
* `Amount` is invalid (negaitve or out of int256 bound)
* `To` address is invalid (non valid ethereum hex address)

#### `DynamicFeeTx` <a href="#dynamicfeetx" id="dynamicfeetx"></a>

The transaction data of EIP-1559 dynamic fee transactions.

```go
type DynamicFeeTx struct {
 // destination EVM chain ID
 ChainID *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,1,opt,name=chain_id,json=chainId,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"chainID"`
 // nonce corresponds to the account nonce (transaction sequence).
 Nonce uint64 `protobuf:"varint,2,opt,name=nonce,proto3" json:"nonce,omitempty"`
 // gas tip cap defines the max value for the gas tip
 GasTipCap *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,3,opt,name=gas_tip_cap,json=gasTipCap,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"gas_tip_cap,omitempty"`
 // gas fee cap defines the max value for the gas fee
 GasFeeCap *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,4,opt,name=gas_fee_cap,json=gasFeeCap,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"gas_fee_cap,omitempty"`
 // gas defines the gas limit defined for the transaction.
 GasLimit uint64 `protobuf:"varint,5,opt,name=gas,proto3" json:"gas,omitempty"`
 // hex formatted address of the recipient
 To string `protobuf:"bytes,6,opt,name=to,proto3" json:"to,omitempty"`
 // value defines the the transaction amount.
 Amount *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,7,opt,name=value,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"value,omitempty"`
 // input defines the data payload bytes of the transaction.
 Data     []byte     `protobuf:"bytes,8,opt,name=data,proto3" json:"data,omitempty"`
 Accesses AccessList `protobuf:"bytes,9,rep,name=accesses,proto3,castrepeated=AccessList" json:"accessList"`
 // v defines the signature value
 V []byte `protobuf:"bytes,10,opt,name=v,proto3" json:"v,omitempty"`
 // r defines the signature value
 R []byte `protobuf:"bytes,11,opt,name=r,proto3" json:"r,omitempty"`
 // s define the signature value
 S []byte `protobuf:"bytes,12,opt,name=s,proto3" json:"s,omitempty"`
}
```

This message field validation is expected to fail if:

* `GasTipCap` is invalid (`nil` , negative or overflows int256)
* `GasFeeCap` is invalid (`nil` , negative or overflows int256)
* `GasFeeCap` is less than `GasTipCap`
* `Fee` (gas price \* gas limit) is invalid (overflows int256)
* `Amount` is invalid (negative or overflows int256)
* `To` address is invalid (non-valid ethereum hex address)
* `ChainID` is `nil`

#### `AccessListTx` <a href="#accesslisttx" id="accesslisttx"></a>

The transaction data of EIP-2930 access list transactions.

```go
type AccessListTx struct {
 // destination EVM chain ID
 ChainID *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,1,opt,name=chain_id,json=chainId,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"chainID"`
 // nonce corresponds to the account nonce (transaction sequence).
 Nonce uint64 `protobuf:"varint,2,opt,name=nonce,proto3" json:"nonce,omitempty"`
 // gas price defines the value for each gas unit
 GasPrice *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,3,opt,name=gas_price,json=gasPrice,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"gas_price,omitempty"`
 // gas defines the gas limit defined for the transaction.
 GasLimit uint64 `protobuf:"varint,4,opt,name=gas,proto3" json:"gas,omitempty"`
 // hex formatted address of the recipient
 To string `protobuf:"bytes,5,opt,name=to,proto3" json:"to,omitempty"`
 // value defines the unsigned integer value of the transaction amount.
 Amount *github_com_cosmos_cosmos_sdk_types.Int `protobuf:"bytes,6,opt,name=value,proto3,customtype=github.com/cosmos/cosmos-sdk/types.Int" json:"value,omitempty"`
 // input defines the data payload bytes of the transaction.
 Data     []byte     `protobuf:"bytes,7,opt,name=data,proto3" json:"data,omitempty"`
 Accesses AccessList `protobuf:"bytes,8,rep,name=accesses,proto3,castrepeated=AccessList" json:"accessList"`
 // v defines the signature value
 V []byte `protobuf:"bytes,9,opt,name=v,proto3" json:"v,omitempty"`
 // r defines the signature value
 R []byte `protobuf:"bytes,10,opt,name=r,proto3" json:"r,omitempty"`
 // s define the signature value
 S []byte `protobuf:"bytes,11,opt,name=s,proto3" json:"s,omitempty"`
}
```

This message field validation is expected to fail if:

* `GasPrice` is invalid (`nil` , negative or overflows int256)
* `Fee` (gas price \* gas limit) is invalid (overflows int256)
* `Amount` is invalid (negative or overflows int256)
* `To` address is invalid (non-valid ethereum hex address)
* `ChainID` is `nil`