# Ethereum

Klaytn provides wrapped transaction types to support Ethereum compatibility. Ethereum transaction types in Klaytn have the same attributes and RLP encoding schemes with Ethereum's design except for the single-byte type delimiter called `EthereumTxTypeEnvelope`. Therefore, users can successfully deploy transactions generated by Ethereum development tools on Klaytn. The type delimiter is also omitted when users use `eth` namespace APIs, so they can use Klaytn just as if they were using Ethereum. Using `klay` namespace APIs, users can deploy and retrieve Ethereum formatted transactions as a type of Klaytn transactions without getting confused with the existing Klaytn transaction types.

## EthereumTxTypeEnvelope <a href="#ethereumtxtypeenvelope" id="ethereumtxtypeenvelope"></a>

EthereumTxTypeEnvelope is a single-byte prefix for raw transactions that denotes Ethereum transaction types. Ethereum has adopted an extendable transaction type scheme from [EIP-2718](https://eips.ethereum.org/EIPS/eip-2718) and it uses a type numbering system that conflicts with Klaytn's. To resolve the conflict between two different transaction type schemes, Klaytn has introduced `EthereumTxTypeEnvelope` which allows for separation and expansion for future Ethereum transaction types.

`EthereumTxTypeEnvelope` is an additional type delimiter and used only for raw transactions and type numbering. It is not used for transaction hash or signature hash. For that purpose, `EthereumTransactionType` as defined in EIPs is used.

* EthereumTxTypeEnvelope: `0x78`
* TxHashRLP : EthereumTransactionType || TransactionPayload
* RawTransaction : EthereumTxTypeEnvelope || EthereumTransactionType || TransactionPayload

## TxTypeEthereumAccessList <a href="#txtypeethereumaccesslist" id="txtypeethereumaccesslist"></a>

`TxTypeEthereumAccessList` represents a type of Ethereum transaction specified in [EIP-2930](https://eips.ethereum.org/EIPS/eip-2930). This transactions type contains an access list, a list of addresses and storage keys that the transaction is supposed to access. Since this transaction type exists to support compatibility, it only works with EOAs associated with \[AccountKeyLegacy]. EOAs associated with other account key types should use other transaction types such as `TxTypeValueTransfer`, `TxTypeSmartContractExecution`, and so on. This transaction type can create accounts, transfer tokens, deploy/execute smart contracts or a mix of the aforementioned.

{% hint style="success" %}
NOTE: Klaytn networks can process this transaction type after the `EthTxTypeCompatibleBlock`
{% endhint %}

{% hint style="success" %}
NOTE: This transaction type only supports the format of the Ethereum transaction type. Unlike [EIP-2930](https://eips.ethereum.org/EIPS/eip-2930), there are no benefits in terms of transaction fee from using access list.
{% endhint %}

### Attributes <a href="#attributes" id="attributes"></a>

| Attribute  | Type                  | Description                                                                                                                                                                                                                                                         |
| ---------- | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| type       | uint8 (Go)            | The type of `TxTypeEthereumAccessList` that is a concatenation of `EthereumTxTypeEnvelope` and `EthereumTransactionType`. This must be 0x7801.                                                                                                                      |
| chainId    | \*big.Int (Go)        | The destination chain ID.                                                                                                                                                                                                                                           |
| nonce      | uint64 (Go)           | A value used to uniquely identify a sender’s transaction. If two transactions with the same nonce are generated by a sender, only one is executed.                                                                                                                  |
| gasPrice   | \*big.Int (Go)        | A multiplier to get how much the sender will pay in tokens. The amount of tokens the sender will pay is calculated via `gas` \* `gasPrice`. For example, the sender will pay 10 KLAY for a transaction fee if gas is 10 and gasPrice is 10^18. See \[Unit of KLAY]. |
| gas        | uint64 (Go)           | The maximum amount of transaction fee the transaction is allowed to use.                                                                                                                                                                                            |
| to         | \*common.Address (Go) | The account address that will receive the transferred value.                                                                                                                                                                                                        |
| value      | \*big.Int (Go)        | The amount of KLAY in `peb` to be transferred.                                                                                                                                                                                                                      |
| data       | \[]byte (Go)          | Data attached to the transaction, used for transaction execution.                                                                                                                                                                                                   |
| accessList | type.AccessList (Go)  | A list of addresses and storage keys consisting of \[]\(common.Address, \[]common.Hash).                                                                                                                                                                            |
| v, r, s    | \*big.Int (Go)        | The cryptographic signature generated by the sender to let the receiver obtain the sender's address.                                                                                                                                                                |

### RLP Encoding for Signature <a href="#rlp-encoding-for-signature" id="rlp-encoding-for-signature"></a>

To make a signature for this transaction type, the RLP serialization proceeds as follows:

{% hint style="success" %}
NOTE: This type of transaction should be signed with London Signer
{% endhint %}

```javascript
SigRLP = EthereumTransactionType || encode([chainId, nonce, gasPrice, gasLimit, to, value, data, accessList])
SigHash = keccak256(SigRLP)
Signature = sign(SigHash, <private key>)
```

### RLP Encoding for SenderTxHash <a href="#rlp-encoding-for-sendertxhash" id="rlp-encoding-for-sendertxhash"></a>

To obtain `SenderTxHash` for this transaction type, the RLP serialization proceeds as follows:

```javascript
SenderTxHashRLP = EthereumTransactionType || encode([chainId, nonce, gasPrice, gasLimit, to, value, data, accessList, v, r, s])
SenderTxHash = keccak256(SenderTxHashRLP)
Signature = sign(SenderTxHash, <private key>)
```

### RLP Encoding for Transaction Hash <a href="#rlp-encoding-for-transaction-hash" id="rlp-encoding-for-transaction-hash"></a>

To make a transaction hash, the RLP serialization proceeds as follows:

```javascript
TxHashRLP = EthereumTransactionType || encode([chainId, nonce, gasPrice, gasLimit, to, value, data, accessList, v, r, s])
TxHash = keccak256(TxHashRLP)
```

### Raw Transaction <a href="#raw-transaction" id="raw-transaction"></a>

```javascript
RawTx = EthereumTxTypeEnvelope || EthereumTransactionType || encode([chainId, nonce, gasPrice, gasLimit, to, value, data, accessList, v, r, s])
```

### RLP Encoding (Example) <a href="#rlp-encoding-example" id="rlp-encoding-example"></a>

The following shows the result of the RLP serialization and the transaction object:

```javascript
    TX(3a3ab67168de40b1f8a2141a70a4e2f551f90d7814b2fbcb3ac99ad8d8d0b641)
    Contract: false
    Chaind:   0x2
    From:     a94f5374fce5edbc8e2a8697c15331677e6ebf0b
    To:       7b65b75d204abed71587c9e519a89277766ee1d0
    Nonce:    1234
    GasPrice: 0x19
    GasLimit  0xf4240
    Value:    0xa
    Data:     0x31323334
    AccessList: [{0000000000000000000000000000000000000001 [0000000000000000000000000000000000000000000000000000000000000000]}]
    V:        0x1
    R:        0xbfc80a874c43b71b67c68fa5927d1443407f31aef4ec6369bbecdb76fc39b0c0
    S:        0x193e62c1dd63905aee7073958675dcb45d78c716a9a286b54a496e82cb762f26
    Hex:      7801f8a1028204d219830f4240947b65b75d204abed71587c9e519a89277766ee1d00a8431323334f838f7940000000000000000000000000000000000000001e1a0000000000000000000000000000000000000000000000000000000000000000001a0bfc80a874c43b71b67c68fa5927d1443407f31aef4ec6369bbecdb76fc39b0c0a0193e62c1dd63905aee7073958675dcb45d78c716a9a286b54a496e82cb762f26
        

```

### RPC Output (Example) <a href="#rpc-output-example" id="rpc-output-example"></a>

The following shows a transaction object returned via JSON RPC.

The return of `eth_getTransactionByHash`

```javascript
{
  "blockHash": "0x7bd7e8a92ecaa5781a15a8b6fff589f8ac8a79325b517a1ba5d5f2f3d7af1b00",
  "blockNumber": "0x1c8f4b",
  "from": "0x5618e15ec2916bbe6cf2cce20ce31e61d6062cac",
  "gas": "0x174876e800",
  "gasPrice": "0x5d21dba00",
  "hash": "0x3f67e48c2090f560234f555cd4edf7853b6327aa9a6a795be1efe3f360dac118",
  "input": "0x1122",
  "nonce": "0x11",
  "to": "0x5dce87b5bfcde54023811b168dc97a9f10913957",
  "transactionIndex": "0x0",
  "value": "0x186a0",
  "type": "0x1",
  "accessList": [
      {
          "address": "0x0000000000000000000000000000000000000001",
          "storageKeys": [
              "0x0000000000000000000000000000000000000000000000000000000000000000"
          ]
      }
  ],
  "chainId": "0x2710",
  "v": "0x1",
  "r": "0xebb2d2144293c257e27aaa1d22156f322b0d2d7385257f186c117899d791f174",
  "s": "0x5cea970287c9f0f9754050a552c458c066d8f3b3e4639f561b22ce4cb7553ac0"
}
```

The return of `klay_getTransactionByHash`

```javascript
{
  "accessList": [
      {
          "address": "0x0000000000000000000000000000000000000001",
          "storageKeys": [
              "0x0000000000000000000000000000000000000000000000000000000000000000"
          ]
      }
  ],
  "blockHash": "0x7bd7e8a92ecaa5781a15a8b6fff589f8ac8a79325b517a1ba5d5f2f3d7af1b00",
  "blockNumber": "0x1c8f4b",
  "chainID": "0x2710",
  "from": "0x5618e15ec2916bbe6cf2cce20ce31e61d6062cac",
  "gas": "0x174876e800",
  "gasPrice": "0x5d21dba00",
  "hash": "0x3f67e48c2090f560234f555cd4edf7853b6327aa9a6a795be1efe3f360dac118",
  "input": "0x1122",
  "nonce": "0x11",
  "senderTxHash": "0x3f67e48c2090f560234f555cd4edf7853b6327aa9a6a795be1efe3f360dac118",
  "signatures": [
      {
          "V": "0x1",
          "R": "0xebb2d2144293c257e27aaa1d22156f322b0d2d7385257f186c117899d791f174",
          "S": "0x5cea970287c9f0f9754050a552c458c066d8f3b3e4639f561b22ce4cb7553ac0"
      }
  ],
  "to": "0x5dce87b5bfcde54023811b168dc97a9f10913957",
  "transactionIndex": "0x0",
  "type": "TxTypeEthereumAccessList",
  "typeInt": 30721,
  "value": "0x186a0"
}
```

## TxTypeEthereumDynamicFee <a href="#txtypeethereumdynamicfee" id="txtypeethereumdynamicfee"></a>

`TxTypeEthereumDynamicFee` represents a type of Ethereum transaction specified in [EIP-1559](https://eips.ethereum.org/EIPS/eip-1559). This transaction type contains `gasTipCap` and `gasFeeCap` instead of `gasPrice`. Since this transaction type exists to support compatibility, it only works with EOAs associated with \[AccountKeyLegacy]. EOAs associated with other account key types should use other transaction types such as `TxTypeValueTransfer`, `TxTypeSmartContractExecution`, and so on. This type of transaction can create accouns, transfer tokens, deploy/execute smart contracts, or a mix of the aforementioned.

{% hint style="success" %}
NOTE: Klaytn networks can process this transaction type after the `EthTxTypeCompatibleBlock`
{% endhint %}

{% hint style="success" %}
NOTE: Currently, this type of transaction only supports the format of the Ethereum transaction type. Unlike [EIP-2930](https://eips.ethereum.org/EIPS/eip-2930), there are no benefits in terms of transaction fees from using access list.
{% endhint %}

{% hint style="success" %}
NOTE: Since Klaytn has a fixed gas price, `gasTipCap` and `gasFeeCap` should take the gas price for the respective network, which is 250 ston at the time of writing.
{% endhint %}

### Attributes <a href="#attributes" id="attributes"></a>

| Attribute  | Type                  | Description                                                                                                                                                                                                                                                                                                  |
| ---------- | --------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| type       | uint8 (Go)            | The type of `TxTypeEthereumDynamicFee` that is a concatenation of `EthereumTxTypeEnvelope` and `EthereumTransactionType`. It must be `0x7802`.                                                                                                                                                               |
| chainId    | \*big.Int (Go)        | The destination chain ID.                                                                                                                                                                                                                                                                                    |
| nonce      | uint64 (Go)           | A value used to uniquely identify a sender’s transaction. If two transactions with the same nonce are generated by a sender, only one is executed.                                                                                                                                                           |
| gasTipCap  | \*big.Int (Go)        | A multiplier to get how much the sender will pay in addition to `baseFee`. Since Klaytn has a fixed gas price, `gasTipCap` and `gasFeeCap` should take the gas price for the respective network, which is 250 ston at the time of writing.                                                                   |
| gasFeeCap  | \*big.Int (Go)        | A multiplier to get how much the sender will pay in tokens. The amount of tokens the sender will pay is calculated via `gas` \* `gasFeeCap`. Since Klaytn has a fixed gas price, `gasTipCap` and `gasFeeCap` should take the gas price for the respective network, which is 250 ston at the time of writing. |
| gas        | uint64 (Go)           | The maximum amount of transaction fee the transaction is allowed to use.                                                                                                                                                                                                                                     |
| to         | \*common.Address (Go) | The account address that will receive the transferred value.                                                                                                                                                                                                                                                 |
| value      | \*big.Int (Go)        | The amount of KLAY in `peb` to be transferred.                                                                                                                                                                                                                                                               |
| data       | \[]byte (Go)          | Data attached to the transaction, used for transaction execution.                                                                                                                                                                                                                                            |
| accessList | type.AccessList (Go)  | A list of addresses and storage keys consisting of \[]\(common.Address, \[]common.Hash).                                                                                                                                                                                                                     |
| v, r, s    | \*big.Int (Go)        | The cryptographic signature generated by the sender to let the receiver obtain the sender's address.                                                                                                                                                                                                         |

### RLP Encoding for Signature <a href="#rlp-encoding-for-signature" id="rlp-encoding-for-signature"></a>

To make a signature for this transaction type, the RLP serialization proceeds as follows:

{% hint style="success" %}
NOTE: This type of transaction should be signed with London Signer
{% endhint %}

```javascript
SigRLP = EthereumTransactionType || encode([chainId, nonce, gasTipCap, gasFeeCap, gasLimit, to, value, data, accessList])
SigHash = keccak256(SigRLP)
Signature = sign(SigHash, <private key>)
```

### RLP Encoding for SenderTxHash <a href="#rlp-encoding-for-sendertxhash" id="rlp-encoding-for-sendertxhash"></a>

To obtain `SenderTxHash` for this transaction type, the RLP serialization proceeds as follows:

```javascript
SenderTxHashRLP = EthereumTransactionType || encode([chainId, nonce, gasTipCap, gasFeeCap, gasLimit, to, value, data, accessList, v, r, s])
SenderTxHash = keccak256(SenderTxHashRLP)
Signature = sign(SenderTxHash, <private key>)
```

### RLP Encoding for Transaction Hash <a href="#rlp-encoding-for-transaction-hash" id="rlp-encoding-for-transaction-hash"></a>

To obtain a transaction hash, the RLP serialization proceeds as follows:

```javascript
TxHashRLP = EthereumTransactionType || encode([chainId, nonce, gasTipCap, gasFeeCap, gasLimit, to, value, data, accessList, v, r, s])
TxHash = keccak256(TxHashRLP)
```

### Raw Transaction <a href="#raw-transaction" id="raw-transaction"></a>

```javascript
RawTx = EthereumTxTypeEnvelope || EthereumTransactionType || encode([chainId, nonce, gasTipCap, gasFeeCap, gasLimit, to, value, data, accessList, v, r, s])
```

### RLP Encoding (Example) <a href="#rlp-encoding-example" id="rlp-encoding-example"></a>

The following shows the result of the RLP serialization and the transaction object:

```javascript
    TX(be74e122acf00c2f257e8698ecf01140b58b2880de3f24d0875730425eccb45a)
    Contract: false
    Chaind:   0x2
    From:     a94f5374fce5edbc8e2a8697c15331677e6ebf0b
    To:       7b65b75d204abed71587c9e519a89277766ee1d0
    Nonce:    1234
    GasTipCap: 0x19
    GasFeeCap: 0x19
    GasLimit  0xf4240
    Value:    0xa
    Data:     0x31323334
    AccessList: [{0000000000000000000000000000000000000001 [0000000000000000000000000000000000000000000000000000000000000000]}]
    V:        0x0
    R:        0xca14aa0bada2da7ca1b143c16e2dd4a69f2a1e77ce54c7f6d440fe828a777f4f
    S:        0x117f0f78aed398b2995b5ee7c67ace25d52be3c72c1384c2aaa9683b351556
    Hex:      7802f8a1028204d21919830f4240947b65b75d204abed71587c9e519a89277766ee1d00a8431323334f838f7940000000000000000000000000000000000000001e1a0000000000000000000000000000000000000000000000000000000000000000080a0ca14aa0bada2da7ca1b143c16e2dd4a69f2a1e77ce54c7f6d440fe828a777f4f9f117f0f78aed398b2995b5ee7c67ace25d52be3c72c1384c2aaa9683b351556
```

### RPC Output (Example) <a href="#rpc-output-example" id="rpc-output-example"></a>

The following shows a transaction object returned via JSON RPC.

The return of `eth_getTransactionByHash`

```javascript
{
  "blockHash": "0x55792fe186e3d1515fe35a68c2c8d7977b2d7db184d80526f906c53222b77833",
  "blockNumber": "0x1c944d",
  "from": "0x5618e15ec2916bbe6cf2cce20ce31e61d6062cac",
  "gas": "0x174876e800",
  "gasPrice": "0x5d21dba00",
  "maxFeePerGas": "0x5d21dba00",
  "maxPriorityFeePerGas": "0x5d21dba00",
  "hash": "0x5db239963029ad9ef6c3331b10ae455638316e330b0efdae2cc1f8e86884e66e",
  "input": "0x1122",
  "nonce": "0x13",
  "to": "0xa0f1633f4c666d7fe5ba912bd5caf03d3655ac31",
  "transactionIndex": "0x0",
  "value": "0x186a0",
  "type": "0x2",
  "accessList": [
      {
          "address": "0x0000000000000000000000000000000000000001",
          "storageKeys": [
              "0x0000000000000000000000000000000000000000000000000000000000000000"
          ]
      }
  ],
  "chainId": "0x2710",
  "v": "0x1",
  "r": "0x27e007cbe79fd8cc9b89dd798bdd5aa62d038273bf006c7c3b40e13a938ab807",
  "s": "0x6209bb328855f02fa2671fecb41efd9f191b03ecab5e580227fa2a0674879384"
}
```

The return of `klay_getTransactionByHash`

```javascript
{
  "accessList": [
      {
          "address": "0x0000000000000000000000000000000000000001",
          "storageKeys": [
              "0x0000000000000000000000000000000000000000000000000000000000000000"
          ]
      }
  ],
  "blockHash": "0x55792fe186e3d1515fe35a68c2c8d7977b2d7db184d80526f906c53222b77833",
  "blockNumber": "0x1c944d",
  "chainId": "0x2710",
  "from": "0x5618e15ec2916bbe6cf2cce20ce31e61d6062cac",
  "gas": "0x174876e800",
  "hash": "0x5db239963029ad9ef6c3331b10ae455638316e330b0efdae2cc1f8e86884e66e",
  "input": "0x1122",
  "maxFeePerGas": "0x5d21dba00",
  "maxPriorityFeePerGas": "0x5d21dba00",
  "nonce": "0x13",
  "senderTxHash": "0x5db239963029ad9ef6c3331b10ae455638316e330b0efdae2cc1f8e86884e66e",
  "signatures": [
      {
          "V": "0x1",
          "R": "0x27e007cbe79fd8cc9b89dd798bdd5aa62d038273bf006c7c3b40e13a938ab807",
          "S": "0x6209bb328855f02fa2671fecb41efd9f191b03ecab5e580227fa2a0674879384"
      }
  ],
  "to": "0xa0f1633f4c666d7fe5ba912bd5caf03d3655ac31",
  "transactionIndex": "0x0",
  "type": "TxTypeEthereumDynamicFee",
  "typeInt": 30722,
  "value": "0x186a0"
}
```