迁移recaptcha到v2的隐藏字段

Question

原始代码

            @Html.Hidden("hf-register-publickey", SettingsHelper.CaptaPublicKey, new { id = "hf-register-publickey" })
            <div class="editor-field">
                <script src="@string.Format("{0}/recaptcha/api/challenge?k={1}", SettingsHelper.CaptaHost, SettingsHelper.CaptaPublicKey)" type="text/javascript"></script>
                <div id="captcha_contain"></div>
              <noscript>
                    <iframe src="@string.Format("{0}/recaptcha/api/noscript?k={1}", SettingsHelper.CaptaHost, SettingsHelper.CaptaPublicKey)"
                            height="300" width="500" frameborder="0"></iframe>
                    <br />
                    <textarea id="recaptcha_challenge_field" name="recaptcha_challenge_field" rows="3" cols="40">
             </textarea>
                    <input type="hidden" id="recaptcha_response_field" name="recaptcha_response_field" value="manual_challenge"></input>
                </noscript>
            </div>

我的问题在第一行。我还需要v2的隐藏字段吗？我找不到任何解决此问题的文档。