> ## Documentation Index > Fetch the complete documentation index at: https://auth0.com/llms.txt > Use this file to discover all available pages before exploring further. # 回復コードを使用したチャレンジ > デバイスまたはアカウントへのアクセスを失ったユーザーに回復コードを使用してチャレンジするために、MFA APIを使用する方法を説明します。 export const AuthCodeGroup = ({children, dropdown}) => { const [processedChildren, setProcessedChildren] = useState(children); useEffect(() => { let unsubscribe = null; function init() { unsubscribe = window.autorun(() => { const processChildren = node => { if (typeof node === "string") { let processedNode = node; for (const [key, value] of window.rootStore.variableStore.values.entries()) { const escapedKey = key.replaceAll(/[.*+?^${}()|[\]\\]/g, (String.raw)`\$&`); processedNode = processedNode.replaceAll(new RegExp(escapedKey, "g"), value); } return processedNode; } else if (Array.isArray(node)) { return node.map(processChildren); } else if (node && node.props && node.props.children) { return { ...node, props: { ...node.props, children: processChildren(node.props.children) } }; } return node; }; setProcessedChildren(processChildren(children)); }); } if (window.rootStore) { init(); } else { window.addEventListener("adu:storeReady", init); } return () => { window.removeEventListener("adu:storeReady", init); unsubscribe?.(); }; }, [children]); return {processedChildren}; }; export const AuthCodeBlock = ({filename, icon, language, highlight, children}) => { const [displayText, setDisplayText] = useState(children); const [copyText, setCopyText] = useState(children); const wrapperRef = React.useRef(null); useEffect(() => { let unsubscribe = null; function init() { if (!window.autorun || !window.rootStore) { return; } unsubscribe = window.autorun(() => { let processedChildrenForDisplay = children; let processedChildrenForCopy = children; for (const [key, value] of window.rootStore.variableStore.values.entries()) { const escapedKey = key.replaceAll(/[.*+?^${}()|[\]\\]/g, (String.raw)`\$&`); let displayValue = value; if (key === "{yourClientSecret}" && value !== "{yourClientSecret}") { displayValue = value.substring(0, 3) + "*****MASKED*****"; } processedChildrenForDisplay = processedChildrenForDisplay.replaceAll(new RegExp(escapedKey, "g"), displayValue); processedChildrenForCopy = processedChildrenForCopy.replaceAll(new RegExp(escapedKey, "g"), value); } setDisplayText(processedChildrenForDisplay); setCopyText(processedChildrenForCopy); }); } if (window.rootStore) { init(); } else { window.addEventListener("adu:storeReady", init); } return () => { window.removeEventListener("adu:storeReady", init); unsubscribe?.(); }; }, [children]); useEffect(() => { if (!wrapperRef.current) return; const originalWriteText = navigator.clipboard.writeText.bind(navigator.clipboard); let isOverriding = false; const handleClick = e => { const button = e.target.closest('[data-testid="copy-code-button"]'); if (!button || !wrapperRef.current.contains(button)) return; isOverriding = true; navigator.clipboard.writeText = text => { if (isOverriding) { isOverriding = false; navigator.clipboard.writeText = originalWriteText; return originalWriteText(copyText); } return originalWriteText(text); }; setTimeout(() => { if (isOverriding) { isOverriding = false; navigator.clipboard.writeText = originalWriteText; } }, 100); }; const wrapper = wrapperRef.current; wrapper.addEventListener('click', handleClick, true); return () => { wrapper.removeEventListener('click', handleClick, true); if (navigator.clipboard.writeText !== originalWriteText) { navigator.clipboard.writeText = originalWriteText; } }; }, [copyText]); return
{displayText}
; }; テナントに対する[回復コードが有効](/docs/ja-jp/secure/multi-factor-authentication/configure-recovery-codes-for-mfa)になると、Auth0は、ユーザーが多要素認証（MFA）に登録したときに自動的に回復コードを生成します。ユーザーは回復コードを保存する必要があります。このコードは後で、ユーザーがMFAに使用されるデバイスまたはアカウントへのアクセスを失った場合に使用されます。 回復コードが無効になると、ユーザーの最初のMFA要素と関連付けたとき、MFA APIは回復コードを返さないため、ユーザーは回復コードで認証できません。 MFA APIを使用して回復コードでユーザーが認証できるようにします。 1. 回復コードを入力するようユーザーに促します。この値は、ユーザーを認証するためにアプリケーションに入力される必要があります。 Auth0は、DUOやレガシーの`google-authenticator`要素向けに復旧コードを生成しません。 2. 回復コードで認証します。回復コードでOAuthトークンエンドポイントを呼び出し、認証して、新しい回復コードを生成します。以下のパラメーターを指定する必要があります。 | パラメーター | 値 | | --------------- | ----------------------------------------------------- | | `grant_type` | `http://auth0.com/oauth/grant-type/mfa-recovery-code` | | `recovery_code` | ユーザーによって提供された回復コード。 | ```bash cURL theme={null} curl --request POST \ --url 'https://{yourDomain}/oauth/token' \ --header 'content-type: application/x-www-form-urlencoded' \ --data grant_type=http://auth0.com/oauth/grant-type/mfa-recovery-code \ --data 'client_id={yourClientId}' \ --data 'client_secret={yourClientSecret}' \ --data 'mfa_token={mfaToken}' \ --data 'recovery_code={recoveryCode}' ``` ```csharp C# theme={null} var client = new RestClient("https://{yourDomain}/oauth/token"); var request = new RestRequest(Method.POST); request.AddHeader("content-type", "application/x-www-form-urlencoded"); request.AddParameter("application/x-www-form-urlencoded", "grant_type=http%3A%2F%2Fauth0.com%2Foauth%2Fgrant-type%2Fmfa-recovery-code&client_id={yourClientId}&client_secret=%7ByourClientSecret%7D&mfa_token=%7BmfaToken%7D&recovery_code=%7BrecoveryCode%7D", ParameterType.RequestBody); IRestResponse response = client.Execute(request); ``` ```go Go theme={null} package main import ( "fmt" "strings" "net/http" "io/ioutil" ) func main() { url := "https://{yourDomain}/oauth/token" payload := strings.NewReader("grant_type=http%3A%2F%2Fauth0.com%2Foauth%2Fgrant-type%2Fmfa-recovery-code&client_id={yourClientId}&client_secret=%7ByourClientSecret%7D&mfa_token=%7BmfaToken%7D&recovery_code=%7BrecoveryCode%7D") req, _ := http.NewRequest("POST", url, payload) req.Header.Add("content-type", "application/x-www-form-urlencoded") res, _ := http.DefaultClient.Do(req) defer res.Body.Close() body, _ := ioutil.ReadAll(res.Body) fmt.Println(res) fmt.Println(string(body)) } ``` ```java Java theme={null} HttpResponse response = Unirest.post("https://{yourDomain}/oauth/token") .header("content-type", "application/x-www-form-urlencoded") .body("grant_type=http%3A%2F%2Fauth0.com%2Foauth%2Fgrant-type%2Fmfa-recovery-code&client_id={yourClientId}&client_secret=%7ByourClientSecret%7D&mfa_token=%7BmfaToken%7D&recovery_code=%7BrecoveryCode%7D") .asString(); ``` ```javascript Node.JS theme={null} var axios = require("axios").default; var options = { method: 'POST', url: 'https://{yourDomain}/oauth/token', headers: {'content-type': 'application/x-www-form-urlencoded'}, data: new URLSearchParams({ grant_type: 'http://auth0.com/oauth/grant-type/mfa-recovery-code', client_id: '{yourClientId}', client_secret: '{yourClientSecret}', mfa_token: '{mfaToken}', recovery_code: '{recoveryCode}' }) }; axios.request(options).then(function (response) { console.log(response.data); }).catch(function (error) { console.error(error); }); ``` ```objc Obj-C theme={null} #import NSDictionary *headers = @{ @"content-type": @"application/x-www-form-urlencoded" }; NSMutableData *postData = [[NSMutableData alloc] initWithData:[@"grant_type=http://auth0.com/oauth/grant-type/mfa-recovery-code" dataUsingEncoding:NSUTF8StringEncoding]]; [postData appendData:[@"&client_id={yourClientId}" dataUsingEncoding:NSUTF8StringEncoding]]; [postData appendData:[@"&client_secret={yourClientSecret}" dataUsingEncoding:NSUTF8StringEncoding]]; [postData appendData:[@"&mfa_token={mfaToken}" dataUsingEncoding:NSUTF8StringEncoding]]; [postData appendData:[@"&recovery_code={recoveryCode}" dataUsingEncoding:NSUTF8StringEncoding]]; NSMutableURLRequest *request = [NSMutableURLRequest requestWithURL:[NSURL URLWithString:@"https://{yourDomain}/oauth/token"] cachePolicy:NSURLRequestUseProtocolCachePolicy timeoutInterval:10.0]; [request setHTTPMethod:@"POST"]; [request setAllHTTPHeaderFields:headers]; [request setHTTPBody:postData]; NSURLSession *session = [NSURLSession sharedSession]; NSURLSessionDataTask *dataTask = [session dataTaskWithRequest:request completionHandler:^(NSData *data, NSURLResponse *response, NSError *error) { if (error) { NSLog(@"%@", error); } else { NSHTTPURLResponse *httpResponse = (NSHTTPURLResponse *) response; NSLog(@"%@", httpResponse); } }]; [dataTask resume]; ``` ```php PHP theme={null} $curl = curl_init(); curl_setopt_array($curl, [ CURLOPT_URL => "https://{yourDomain}/oauth/token", CURLOPT_RETURNTRANSFER => true, CURLOPT_ENCODING => "", CURLOPT_MAXREDIRS => 10, CURLOPT_TIMEOUT => 30, CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1, CURLOPT_CUSTOMREQUEST => "POST", CURLOPT_POSTFIELDS => "grant_type=http%3A%2F%2Fauth0.com%2Foauth%2Fgrant-type%2Fmfa-recovery-code&client_id={yourClientId}&client_secret=%7ByourClientSecret%7D&mfa_token=%7BmfaToken%7D&recovery_code=%7BrecoveryCode%7D", CURLOPT_HTTPHEADER => [ "content-type: application/x-www-form-urlencoded" ], ]); $response = curl_exec($curl); $err = curl_error($curl); curl_close($curl); if ($err) { echo "cURL Error #:" . $err; } else { echo $response; } ``` ```python Python theme={null} import http.client conn = http.client.HTTPSConnection("") payload = "grant_type=http%3A%2F%2Fauth0.com%2Foauth%2Fgrant-type%2Fmfa-recovery-code&client_id={yourClientId}&client_secret=%7ByourClientSecret%7D&mfa_token=%7BmfaToken%7D&recovery_code=%7BrecoveryCode%7D" headers = { 'content-type': "application/x-www-form-urlencoded" } conn.request("POST", "/{yourDomain}/oauth/token", payload, headers) res = conn.getresponse() data = res.read() print(data.decode("utf-8")) ``` ```ruby Ruby theme={null} require 'uri' require 'net/http' require 'openssl' url = URI("https://{yourDomain}/oauth/token") http = Net::HTTP.new(url.host, url.port) http.use_ssl = true http.verify_mode = OpenSSL::SSL::VERIFY_NONE request = Net::HTTP::Post.new(url) request["content-type"] = 'application/x-www-form-urlencoded' request.body = "grant_type=http%3A%2F%2Fauth0.com%2Foauth%2Fgrant-type%2Fmfa-recovery-code&client_id={yourClientId}&client_secret=%7ByourClientSecret%7D&mfa_token=%7BmfaToken%7D&recovery_code=%7BrecoveryCode%7D" response = http.request(request) puts response.read_body ``` ```swift Swift theme={null} import Foundation let headers = ["content-type": "application/x-www-form-urlencoded"] let postData = NSMutableData(data: "grant_type=http://auth0.com/oauth/grant-type/mfa-recovery-code".data(using: String.Encoding.utf8)!) postData.append("&client_id={yourClientId}".data(using: String.Encoding.utf8)!) postData.append("&client_secret={yourClientSecret}".data(using: String.Encoding.utf8)!) postData.append("&mfa_token={mfaToken}".data(using: String.Encoding.utf8)!) postData.append("&recovery_code={recoveryCode}".data(using: String.Encoding.utf8)!) let request = NSMutableURLRequest(url: NSURL(string: "https://{yourDomain}/oauth/token")! as URL, cachePolicy: .useProtocolCachePolicy, timeoutInterval: 10.0) request.httpMethod = "POST" request.allHTTPHeaderFields = headers request.httpBody = postData as Data let session = URLSession.shared let dataTask = session.dataTask(with: request as URLRequest, completionHandler: { (data, response, error) -> Void in if (error != nil) { print(error) } else { let httpResponse = response as? HTTPURLResponse print(httpResponse) } }) dataTask.resume() ``` 3. 回復コードを保存するようにユーザーに求めます。呼び出しに成功した場合は、認証トークンと新しい回復コードを受け取ります。 ```json lines theme={null} { "access_token": "O3...H4", "id_token": "eyJh...w", "scope": "openid profile", "expires_in": 86400, "recovery_code": "K6LGLV3RSH3VERMKET8L7QKU", "token_type": "Bearer" } ``` 4. 新しい回復コードが生成されたことを通知し、それを保存するようにユーザーに求めます。 ## もっと詳しく * [SMSおよび音声Authenticatorの登録とチャレンジ](/docs/ja-jp/secure/multi-factor-authentication/authenticate-using-ropg-flow-with-mfa/enroll-challenge-sms-voice-authenticators) * [プッシュAuthenticatorの登録とチャレンジ](/docs/ja-jp/secure/multi-factor-authentication/authenticate-using-ropg-flow-with-mfa/enroll-and-challenge-push-authenticators) * [OTP Authenticatorの登録とチャレンジ](/docs/ja-jp/secure/multi-factor-authentication/authenticate-using-ropg-flow-with-mfa/enroll-and-challenge-otp-authenticators) * [メールAuthenticatorの登録とチャレンジ](/docs/ja-jp/secure/multi-factor-authentication/authenticate-using-ropg-flow-with-mfa/enroll-and-challenge-email-authenticators) * [Auth0 MFA APIについて](/docs/ja-jp/secure/multi-factor-authentication/multi-factor-authentication-developer-resources/mfa-api) * [認証APIを使って認証要素を管理する](/docs/ja-jp/secure/multi-factor-authentication/manage-mfa-auth0-apis/manage-authenticator-factors-mfa-api)