I have been building my project using React Native which allows me to build a native app for both Android and iOS. However, Android requires hash key especially when you try to use SDK to implement things like social login.
The command is really simple.
keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore -alias androiddebugkey -storepass android -keypass android | openssl sha1 -binary | openssl base64
This will generate a line with a hash key which I will not print here for a security purpose. You just have to add the value to the field where the hash key is required