> ## Documentation Index
> Fetch the complete documentation index at: https://docs.buzz-up.io/llms.txt
> Use this file to discover all available pages before exploring further.

# eth_signTypedData_v4

> eth_signTypedData_v4 是以太坊 JSON-RPC API 的一个方法，用于执行 EIP-712 的签名。这个方法允许 dApp 安全地请求用户对一个结构化数据的签名，以确保用户确认该数据的内容。

***

### 参数 TypedData

* <div>domain <span style={{color:'#707070',fontSize:14}}>object</span></div>
* <div>message <span style={{color:'#707070',fontSize:14}}>object</span></div>
* <div>primaryType <span style={{color:'#707070',fontSize:14}}>string</span></div>
* <div>types <span style={{color:'#707070',fontSize:14}}>string</span></div>

***

### 返回值

* Signature string
* hex encoded bytes

### Request

```javascript theme={null}
const signTypedData = async () => {
  const address = "0xYourEthereumAddress";
   const msgParams = {
      domain: {
        chainId: 97, // Binance Smart Chain 测试网
        name: "Ether Mail",
        verifyingContract: "0xCcCCccccCCCCcCCCCCCcCcCccCcCCCcCcccccccC",
        version: "1", // 版本应为字符串
      },
      message: {
        from: {
          name: 'Alice',
          wallet: "0x58F401144bbd45031b9937Ec93A8b2aac8bB8972" // 确保地址为小写
        },
        to: {
          name: 'Bob',
          wallet: '0x58F401144bbd45031b9937Ec93A8b2aac8bB8972' // 确保地址为小写
        },
        contents: 'Hello, Bob!'
      },
      primaryType: "Mail",
      types: {
        EIP712Domain: [
          { name: 'name', type: 'string' },
          { name: 'version', type: 'string' },
          { name: 'chainId', type: 'uint256' },
          { name: 'verifyingContract', type: 'address' }
        ],
        Person: [
          { name: 'name', type: 'string' },
          { name: 'wallet', type: 'address' }
        ],
        Mail: [
          { name: 'from', type: 'Person' },
          { name: 'to', type: 'Person' },
          { name: 'contents', type: 'string' }
        ]
      },
    };

  try {
    const signature = await window.ethereum.request({
    method: "eth_signTypedData_v4",
    params: [address, JSON.stringify(msgParams)],
  });

    console.log("签名结果:", signature);
  } catch (error) {
    console.log("签名失败:", error);
  }
};
```