Does it threaten something bad if you sign several android applications with one certificate?

Question

Android

Does it threaten something bad if you sign several android applications with one certificate?

Answer 1

No, it doesn't threaten anything. Moreover, there are goodies - for example, they can use perms with the level signature , they can fumble cache files.

Answer 2

If the source code of one of the applications is published in the public domain and the release keystore somehow got there, then an attacker who hacked into your gplay account will be able to "update" the application with a trojan.
Perhaps he will be able to write his own application that will steal data from yours, although I'm not sure here, MB needs support from both sides of the application.
https://developer.android.com/studio/publish/app-s...

• App upgrade: When the system is installing an update to an app, it compares the certificate(s) in the new version with those in the existing version. The system allows the update if the certificates match. If you sign the new version with a different certificate, you must assign a different package name to the app—in this case, the user installs the new version as a completely new app.
  
• App modularity: Android allows APKs signed by the same certificate to run in the same process, if the apps so request, so that the system treats them as a single app. In this way you can deploy your app in modules, and users can update each of the modules independently.
  
• Code/data sharing through permissions: Android provides signature-based permissions enforcement, so that an app can expose functionality to another app that is signed with a specified certificate. By signing multiple APKs with the same certificate and using signature-based permissions checks, your apps can share code and data in a secure manner.