우리는 웹에 대한 구글 로그인 자바 스크립트 플랫폼 라이브러리를 중단 . 인증 및 사용자 로그인의 경우, 모두 새로운 Google 아이덴티티 서비스 SDK를 사용하여 안드로이드 대신.

백엔드 서버로 인증

백엔드 서버와 통신하는 앱 또는 사이트에서 Google 로그인을 사용하는 경우 서버에서 현재 로그인한 사용자를 식별해야 할 수 있습니다. 안전하게 하려면 사용자가 성공적으로 로그인한 후 HTTPS를 사용하여 사용자의 ID 토큰을 서버로 보냅니다. 그런 다음 서버에서 ID 토큰의 무결성을 확인하고 토큰에 포함된 사용자 정보를 사용하여 세션을 설정하거나 새 계정을 만듭니다.

서버에 ID 토큰 보내기

사용자가 성공적으로 로그인한 후 사용자의 ID 토큰을 가져옵니다.

function onSignIn(googleUser) {
  var id_token = googleUser.getAuthResponse().id_token;
  ...
}

그런 다음 HTTPS POST 요청을 사용하여 서버에 ID 토큰을 보냅니다.

var xhr = new XMLHttpRequest();
xhr.open('POST', 'https://yourbackend.example.com/tokensignin');
xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
xhr.onload = function() {
  console.log('Signed in as: ' + xhr.responseText);
};
xhr.send('idtoken=' + id_token);

ID 토큰의 무결성 확인

HTTPS POST로 ID 토큰을 받은 후 토큰의 무결성을 확인해야 합니다.

To verify that the token is valid, ensure that the following criteria are satisfied:

  • The ID token is properly signed by Google. Use Google's public keys (available in JWK or PEM format) to verify the token's signature. These keys are regularly rotated; examine the Cache-Control header in the response to determine when you should retrieve them again.
  • The value of aud in the ID token is equal to one of your app's client IDs. This check is necessary to prevent ID tokens issued to a malicious app being used to access data about the same user on your app's backend server.
  • The value of iss in the ID token is equal to accounts.google.com or https://accounts.google.com.
  • The expiry time (exp) of the ID token has not passed.
  • If you want to restrict access to only members of your G Suite domain, verify that the ID token has an hd claim that matches your G Suite domain name.

Rather than writing your own code to perform these verification steps, we strongly recommend using a Google API client library for your platform, or a general-purpose JWT library. For development and debugging, you can call our tokeninfo validation endpoint.

Using a Google API Client Library

Using one of the Google API Client Libraries (e.g. Java, Node.js, PHP, Python) is the recommended way to validate Google ID tokens in a production environment.

Java

To validate an ID token in Java, use the GoogleIdTokenVerifier object. For example:

import com.google.api.client.googleapis.auth.oauth2.GoogleIdToken;
import com.google.api.client.googleapis.auth.oauth2.GoogleIdToken.Payload;
import com.google.api.client.googleapis.auth.oauth2.GoogleIdTokenVerifier;

...

GoogleIdTokenVerifier verifier = new GoogleIdTokenVerifier.Builder(transport, jsonFactory)
    // Specify the CLIENT_ID of the app that accesses the backend:
    .setAudience(Collections.singletonList(CLIENT_ID))
    // Or, if multiple clients access the backend:
    //.setAudience(Arrays.asList(CLIENT_ID_1, CLIENT_ID_2, CLIENT_ID_3))
    .build();

// (Receive idTokenString by HTTPS POST)

GoogleIdToken idToken = verifier.verify(idTokenString);
if (idToken != null) {
  Payload payload = idToken.getPayload();

  // Print user identifier
  String userId = payload.getSubject();
  System.out.println("User ID: " + userId);

  // Get profile information from payload
  String email = payload.getEmail();
  boolean emailVerified = Boolean.valueOf(payload.getEmailVerified());
  String name = (String) payload.get("name");
  String pictureUrl = (String) payload.get("picture");
  String locale = (String) payload.get("locale");
  String familyName = (String) payload.get("family_name");
  String givenName = (String) payload.get("given_name");

  // Use or store profile information
  // ...

} else {
  System.out.println("Invalid ID token.");
}

The GoogleIdTokenVerifier.verify() method verifies the JWT signature, the aud claim, the iss claim, and the exp claim.

If you want to restrict access to only members of your G Suite domain, also verify the hd claim by checking the domain name returned by the Payload.getHostedDomain() method.

Node.js

To validate an ID token in Node.js, use the Google Auth Library for Node.js. Install the library:

npm install google-auth-library --save
Then, call the verifyIdToken() function. For example:

const {OAuth2Client} = require('google-auth-library');
const client = new OAuth2Client(CLIENT_ID);
async function verify() {
  const ticket = await client.verifyIdToken({
      idToken: token,
      audience: CLIENT_ID,  // Specify the CLIENT_ID of the app that accesses the backend
      // Or, if multiple clients access the backend:
      //[CLIENT_ID_1, CLIENT_ID_2, CLIENT_ID_3]
  });
  const payload = ticket.getPayload();
  const userid = payload['sub'];
  // If request specified a G Suite domain:
  // const domain = payload['hd'];
}
verify().catch(console.error);

The verifyIdToken function verifies the JWT signature, the aud claim, the exp claim, and the iss claim.

If you want to restrict access to only members of your G Suite domain, also verify the hd claim matches your G Suite domain name.

PHP

To validate an ID token in PHP, use the Google API Client Library for PHP. Install the library (for example, using Composer):

composer require google/apiclient
Then, call the verifyIdToken() function. For example:

require_once 'vendor/autoload.php';

// Get $id_token via HTTPS POST.

$client = new Google_Client(['client_id' => $CLIENT_ID]);  // Specify the CLIENT_ID of the app that accesses the backend
$payload = $client->verifyIdToken($id_token);
if ($payload) {
  $userid = $payload['sub'];
  // If request specified a G Suite domain:
  //$domain = $payload['hd'];
} else {
  // Invalid ID token
}

The verifyIdToken function verifies the JWT signature, the aud claim, the exp claim, and the iss claim.

If you want to restrict access to only members of your G Suite domain, also verify the hd claim matches your G Suite domain name.

Python

To validate an ID token in Python, use the verify_oauth2_token function. For example:

from google.oauth2 import id_token
from google.auth.transport import requests

# (Receive token by HTTPS POST)
# ...

try:
    # Specify the CLIENT_ID of the app that accesses the backend:
    idinfo = id_token.verify_oauth2_token(token, requests.Request(), CLIENT_ID)

    # Or, if multiple clients access the backend server:
    # idinfo = id_token.verify_oauth2_token(token, requests.Request())
    # if idinfo['aud'] not in [CLIENT_ID_1, CLIENT_ID_2, CLIENT_ID_3]:
    #     raise ValueError('Could not verify audience.')

    # If auth request is from a G Suite domain:
    # if idinfo['hd'] != GSUITE_DOMAIN_NAME:
    #     raise ValueError('Wrong hosted domain.')

    # ID token is valid. Get the user's Google Account ID from the decoded token.
    userid = idinfo['sub']
except ValueError:
    # Invalid token
    pass

The verify_oauth2_token function verifies the JWT signature, the aud claim, and the exp claim. You must also verify the hd claim (if applicable) by examining the object that verify_oauth2_token returns. If multiple clients access the backend server, also manually verify the aud claim.

Calling the tokeninfo endpoint

An easy way to validate an ID token signature for debugging is to use the tokeninfo endpoint. Calling this endpoint involves an additional network request that does most of the validation for you while you test proper validation and payload extraction in your own code. It is not suitable for use in production code as requests may be throttled or otherwise subject to intermittent errors.

To validate an ID token using the tokeninfo endpoint, make an HTTPS POST or GET request to the endpoint, and pass your ID token in the id_token parameter. For example, to validate the token "XYZ123", make the following GET request:

https://oauth2.googleapis.com/tokeninfo?id_token=XYZ123

If the token is properly signed and the iss and exp claims have the expected values, you will get a HTTP 200 response, where the body contains the JSON-formatted ID token claims. Here's an example response:

{
 // These six fields are included in all Google ID Tokens.
 "iss": "https://accounts.google.com",
 "sub": "110169484474386276334",
 "azp": "1008719970978-hb24n2dstb40o45d4feuo2ukqmcc6381.apps.googleusercontent.com",
 "aud": "1008719970978-hb24n2dstb40o45d4feuo2ukqmcc6381.apps.googleusercontent.com",
 "iat": "1433978353",
 "exp": "1433981953",

 // These seven fields are only included when the user has granted the "profile" and
 // "email" OAuth scopes to the application.
 "email": "testuser@gmail.com",
 "email_verified": "true",
 "name" : "Test User",
 "picture": "https://lh4.googleusercontent.com/-kYgzyAWpZzJ/ABCDEFGHI/AAAJKLMNOP/tIXL9Ir44LE/s99-c/photo.jpg",
 "given_name": "Test",
 "family_name": "User",
 "locale": "en"
}

If you are a G Suite customer, you might also be interested in the hd claim, which indicates the hosted domain of the user. This can be used to restrict access to a resource to only members of certain domains. The absence of this claim indicates that the user does not belong to a G Suite hosted domain.

계정 또는 세션 만들기

토큰을 확인한 후 사용자가 이미 사용자 데이터베이스에 있는지 확인하십시오. 그렇다면 사용자에 대해 인증된 세션을 설정하십시오. 사용자가 아직 사용자 데이터베이스에 없으면 ID 토큰 페이로드의 정보에서 새 사용자 레코드를 만들고 사용자에 대한 세션을 설정합니다. 앱에서 새로 생성된 사용자를 감지하면 사용자에게 필요한 추가 프로필 정보를 입력하라는 메시지를 표시할 수 있습니다.

교차 계정 보호로 사용자 계정 보호

Google에 의존하여 사용자를 로그인하면 Google이 사용자 데이터를 보호하기 위해 구축한 모든 보안 기능과 인프라의 이점을 자동으로 활용할 수 있습니다. 그러나 드물게 사용자의 Google 계정이 도용되거나 다른 중요한 보안 이벤트가 있는 경우 앱도 공격에 취약할 수 있습니다. 더 나은 주요 보안 이벤트에서 귀하의 계정을 보호하기 위해 사용 크로스 계정 보호 구글에서 보안 경고를받을 수 있습니다. 이러한 이벤트를 수신하면 사용자의 Google 계정 보안에 대한 중요한 변경 사항에 대한 가시성을 확보한 다음 서비스에 조치를 취하여 계정을 보호할 수 있습니다.