Feature request: Ability to control which scripts can be executed

Right now, the custom script extension doesn't have the ability to limit script sources or script signatures. There are Image Publishers on Azure marketplace that rely on the Custom Script Extension to deploy certain functionality to VMs based on their images (e.g. onboarding onto Azure Security Center). It is not possible to limit scripts to certain sources (e.g. only allow scripts from certain blob storage accounts) or to limit scripts based on signatures (e.g. GPG signatures).

With this issue I would to query the possibility to introduce a functionality to limit script execution. This is useful for publishers to Azure Marketplace. This limit could either be based on source (URL prefix?) or signing capabilities (script signature).