# ERC-4337 UserOperation Hash

## How to calculate UserOperationHash

UserOperationHash = keccak256(abi.encode(hash(pack(op)), entryPointAddress, chainId))

- pack()
- hash()

## UserOperation Struct

struct UserOperation {
    address sender;                   // 0x9fd042a18e90ce326073fa70f111dc9d798d9a52
    uint256 nonce;                    // 123
    bytes initCode;                   // hello (0x68656c6c6f)
    bytes callData;                   // world (0x776F726C64)
    uint256 callGasLimit;             // 1000
    uint256 verificationGasLimit;     // 2300
    uint256 preVerificationGas;       // 3100
    uint256 maxFeePerGas;             // 8500
    uint256 maxPriorityFeePerGas;     // 1
    bytes paymasterAndData;           // blocto (0x626c6f63746f)
    bytes signature;                  // clement (0x636c656d656e74)
}

## `pack()`

#### Code

// `signature` is not included.
function pack(UserOperation calldata userOp) public pure returns (bytes memory ret) {
    address sender = getSender(userOp);
    uint256 nonce = userOp.nonce;
    bytes32 hashInitCode = calldataKeccak(userOp.initCode);
    bytes32 hashCallData = calldataKeccak(userOp.callData);
    uint256 callGasLimit = userOp.callGasLimit;
    uint256 verificationGasLimit = userOp.verificationGasLimit;
    uint256 preVerificationGas = userOp.preVerificationGas;
    uint256 maxFeePerGas = userOp.maxFeePerGas;
    uint256 maxPriorityFeePerGas = userOp.maxPriorityFeePerGas;
    bytes32 hashPaymasterAndData = calldataKeccak(userOp.paymasterAndData);

    return abi.encode(
        sender,
        nonce,
        hashInitCode,
        hashCallData,
        callGasLimit,
        verificationGasLimit,
        preVerificationGas,
        maxFeePerGas,
        maxPriorityFeePerGas,
        hashPaymasterAndData
    );
}

#### Result

0x
sender                  0000000000000000000000009fd042a18e90ce326073fa70f111dc9d798d9a52
nonce                   000000000000000000000000000000000000000000000000000000000000007b
hashInitCode            1c8aff950685c2ed4bc3174f3472287b56d9517b9c948127319a09a7a36deac8
hashCallData            8452c9b9140222b08593a26daa782707297be9f7b3e8281d7b4974769f19afd0
callGasLimit            00000000000000000000000000000000000000000000000000000000000003e8
verificationGasLimit    00000000000000000000000000000000000000000000000000000000000008fc
preVerificationGas      0000000000000000000000000000000000000000000000000000000000000c1c
maxFeePerGas            0000000000000000000000000000000000000000000000000000000000002134
maxPriorityFeePerGas    0000000000000000000000000000000000000000000000000000000000000001
hashPaymasterAndData    87a03e44e7bf9fb10a29733982a339f6a2a22dc7eb1015ae7bb61fc0f710b85d

- `hashInitCode`: keccak256(initCode)
- `hashCallData`: keccak256(callData)
- `hashPaymasterAndData`: keccak256(paymasterAndData)

## `hash()`
#### Code

function hash(UserOperation calldata userOp) public pure returns (bytes32) {
    return keccak256(pack(userOp));
}

#### Result

0xf88f954157adc24e05de4962278d73e5e45f8028c85da59cd23c46f2701d82e3

## `getUserOpHash()`

- hash(from `hash()`): 0xf88f954157adc24e05de4962278d73e5e45f8028c85da59cd23c46f2701d82e3
- entryPointAddress: 0xaE036c65C649172b43ef7156b009c6221B596B8b
- chainId: 0x1

#### Code

keccak256(abi.encode(hash, entryPointAddress, chainId));

#### Result

0xe554d0701f7fdc734f84927d109537f1ac4ee4ebfa3670c71d224a4fa15dbcd1

[
    "0x9fd042a18e90ce326073fa70f111dc9d798d9a52",  
    123, 
    "0x68656c6c6f", 
    "0x776f726c64", 
    1000, 
    2300, 
    3100, 
    8500, 
    1,
    "0x626c6f63746f", 
    "0x636c656d656e74"
]