This is the Windows step I got stuck on after watching Getting started with Firebase in Unity (2019). Firebase asks for the SHA1 of the app signing key. On Windows, the Unity debug keystore is the file named debug.keystore inside the .android folder. keytool is the program that comes with the JDK, and the docs are keytool. I first wrote it up on DEV on 26 July 2022. keytool -list -v prints both the SHA1 and the SHA256. Most of the questions I saw were only asking for the SHA1, but the same command prints the SHA256 as well.

Open CMD and go into the .android folder. On Windows that's usually under your user folder:

cd .android

Then run:

keytool -exportcert -keystore debug.keystore -list -v

Hit enter. It asks for the keystore password. The debug keystore password is android. Type it and hit enter. Nothing shows while you type, so it feels like it's frozen. It isn't. After enter, the certificate block is on screen, and SHA1 and SHA256 are in there.