> ## Documentation Index
> Fetch the complete documentation index at: https://cobo.com/developers/llms.txt
> Use this file to discover all available pages before exploring further.

# Create UCW class

> This operation creates an instance of the UCW class, decrypts the Secrets file, establishes a connection with the Cobo server, and optionally registers a callback endpoint to monitor the connection status.

<Tip>
  Try [Cobo WaaS Skill](/v2/guides/overview/cobo-waas-skill) in your AI coding assistant (Claude Code, Cursor, etc.). Describe your needs in natural language to auto-generate production-ready SDK code and debug faster 🚀
</Tip>

<Info>The UCW class enables you to receive and approve TSS requests and transactions. Additionally, it allows you to export key shares for backing up or restoring the private keys.</Info>

<Info>The UCW class inherits from the UCWPublic class.</Info>

<CodeGroup>
  ```Swift iOS theme={null}
  public init(config: SDKConfig, secretsFile: String, passphrase: String, connCallback: @escaping(ConnCode, String?) -> Void = { _, _ in }) throws
  ```

  ```Dart Flutter theme={null}
  static Future<UCW> create({required SDKConfig config, required String secretsFile, required String passphrase, Function(ConnCode connCode, String connMessage)? connCallback}) async
  ```
</CodeGroup>

<RequestExample>
  ```Swift iOS theme={null}
  let secrets = "secrets.db"
  let passphrase = "d3hxNyoiAP@Lm!D7Qpo_hghdpgyc_r39"
  let sdkConfig = SDKConfig(env: Env.development, timeout: 30, debug: true)
  var sdkInstance: UCW?
  var connCode: ConnCode = .unknown
  var connMessage: String? = ""

  do {
      sdkInstance = try UCW(config: sdkConfig, secretsFile: secrets, passphrase: passphrase) { code, message in
          connCode = code
          connMessage = message
          print("Connection Code: \(connCode), Message: \(connMessage ?? "No message")")
      }
  } catch {
      print("Error: \(error)")
  }
  ```

  ```Dart Flutter theme={null}
  const String secrets = "secrets.db";
  const String passphrase = "d3hxNyoiAP@Lm!D7Qpo_hghdpgyc_r39";

  final sdkConfig = SDKConfig(
      env: Env.development,
      timeout: 30,
      debug: true
  );

  UCW? sdkInstance;
  ConnCode connCode = ConnCode.unknown;
  String? connMessage = "";

  try {
      sdkInstance = await UCW.create(
          config: sdkConfig, 
          secretsFile: secrets, 
          passphrase: passphrase,
          connCallback: (code, message) async {
              connCode = code;
              connMessage = message;
              print("Connection Code: $connCode, Message: ${connMessage ?? 'No message'}");
          }
      );
  } catch (error) {
      print("Error: $error");
  }
  ```
</RequestExample>

## Parameters

<ParamField path="config" type="object">
  The configuration settings for the UCW SDK.

  <Expandable title="child attributes">
    <ParamField path="env" type="enum<string>">
      The environment type. Possible values include:

      * `development`: The operation establishes a connection with the Cobo server's development environment.
      * `production`: The operation establishes a connection with the Cobo server's production environment.
    </ParamField>

    <ParamField path="timeout" type="int32" default="30">
      The timeout duration for obtaining TSS requests and transactions, in seconds.
    </ParamField>

    <ParamField path="debug" type="boolean">
      Whether the debug mode is enabled, which includes outputting debug-level logs.

      * `true`: The debug mode is enabled.

      * `false`: The debug mode is disabled.
    </ParamField>
  </Expandable>
</ParamField>

<ParamField path="secretsFile" type="string">
  The complete file name, including its extension, for the Secrets file that needs decryption.
</ParamField>

<ParamField path="passphrase" type="string">
  The passphrase for decrypting the Secrets file.
</ParamField>

<ParamField path="connCallback" type="function">
  An optional callback function to monitor connection status.

  <Expandable title="child attributes">
    <ParamField path="connCode" type="enum<int32>">
      The connection status code. Possible values include:

      * `1300`: Connected.
      * `1301`: Disconnected.
      * `1302`: Connection closed.
      * `1310`: Connection error.
      * `1311`: URL parse error.
      * `1320`: Connection refused.
      * `1321`: Connection failed.
      * `1350`: Proxy error.
      * `1351`: Proxy parse error.
    </ParamField>

    <ParamField path="connMessage" type="string">
      The message associated with the `connCode`.
    </ParamField>
  </Expandable>
</ParamField>