How to create firebase project with the same SHA-1 key as used in another project?

Question

Is it possible to create two Firebase projects with the same SHA-1? because I have an android project created already and the installed application are targeting that project, now for some reasons I need to use another project for the newer versions of the same applications so the existence of both firebase projects is necessary. But I wonder how would I do it with the same SHA-1 because it gives me error and I am not able to find a way?

The error message says:

An OAuth2 client already exists for this package name and SHA-1 in another project

Answer 1

Read the error message carefully. It says it's using both the package name of the app and the SHA-1. This means you can have the same SHA-1 in two projects, but the package names of the app (also called "application id") must be different. Likewise, you can have two projects that have the same package name, but they can not have any of the same SHA-1 added to them.

The combination of package name and SHA-1 must be unique.