使用Google Play应用签名将同一应用签名证书与其他应用一起使用

Question

I have two different apps, and I want them to be able to communicate together. For security reasons, I would like to restrict the communication with protectionLevel:signature, so I don't have to worry about other apps possibly messing with my apps.

The problem is, I use Google Play Signing for the first app. I noticed, that when I want to create a new App in the play console, and opt-in for Google Play App Signing, that another certificate is generated. So, I suspect that the permission system is not working, as the release-apk that users download will not be signed by the same certificate, and that the "protectionLevel=signature" check will fail.

Is this true, or will it still work somehow when the Upload-Certificate matches? Is there any way to use the same certifiacte for different apps using Google Play App Signing?

Answer 1

I solved it; There is a button for reusing the Signing Key from an old app in the "App Signature" Tab in the play console.

Note that after you generated a distribution key once, it cannot be changed, even if you never uploaded an APK yet, so you have to press the button to reuse the key immediately before generating another distribution key.

I had to delete my (unpublished) app and created a new one. If you already published you app (even if just for a closed beta test), your only chance to get the same distribution key is to create a new app with a different app id.