On a Mac, for generating a key hash, follow the simple steps below.

Open Terminal
Paste Below Command (Step 3) And Hit Return
keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore | openssl sha1 -binary | openssl base64
Enter Password : Android
It will give you Key hash (like MibyjIEJWghOLquRdk9esClXHWH=)
This will give you a debug key hash. Also we can generate a Release key hash with the same Process. Just need to change our keystore path and password.

Happy Coding. Thank You