참고 자료
developers.google.com/android/guides/client-auth?authuser=1
Authenticating Your Client | Android용 Google API | Google Developers
Certain Google Play services (such as Google Sign-in and App Invites) require you to provide the SHA-1 of your signing certificate so we can create an OAuth2 client and API key for your app. To get your SHA-1, follow the instructions to use Keytool or Grad
developers.google.com
developers.google.com/identity/sign-in/android/start-integrating?authuser=1
Start Integrating Google Sign-In into Your Android App
Before you can start integrating Google Sign-In in your own app, you must configure a Google API Console project and set up your Android Studio project. The steps on this page do just that. The next steps then describe how to integrate Google Sign-In into
developers.google.com