XPost: misc.phone.mobile.iphone   
   From: marianjones@helpfulpeople.com   
      
   badgolferman wrote:   
   >> Only iOS embeds identity-bound metadata into delivered free app packages.   
   >> Why?   
   >   
   > I don't know if this has anything to do with your question, but when I   
   > upgrade a device to a newer one all the apps I've got installed on the   
   > previous device are automatically downloaded and installed on the new   
   > device.   
      
   Hi badgolferman,   
      
   Happy New Year!   
      
   It's important for all of us to UNDERSTAND what Apple does to an IPA   
   (which only Apple does, as no other OS vendor does what Apple does).   
      
   What you are describing when you upgrade a device is not app portability.   
      
   It is an account-level re-download. The new device does not receive the   
   actual app package from the old device. Instead, it contacts the App   
   Store and downloads a fresh, Apple-signed, Apple-encrypted build.   
      
   Unlike every other common consumer operating system, iOS app packages are   
   not portable artifacts like APKs, EXEs, DEBs, or RPMs.   
      
   1. App Store builds are re-signed by Apple, not the developer.   
      The developer's signature is removed and replaced with an App Store   
      distribution signature. iOS validates this signature against Apple's   
      certificate chain at install and launch time.   
      
   2. The executable inside the IPA is encrypted with FairPlay DRM.   
      The Mach-O binary is encrypted, and the decryption keys are provisioned   
      per device during installation. These keys cannot be transferred to   
      another device.   
      
   3. The App Store injects identity-bound metadata into the package.   
      This includes account identifiers and device-targeting information.   
      Unlike every other common consumer operating system app installer,   
      an IPA extracted from one device cannot be sideloaded onto another   
      because that identity-bound mothership metadata will not match.   
      
   4. iOS enforces mandatory code signing at the kernel level.   
      The AMFI (Apple Mobile File Integrity) subsystem refuses to execute   
      any binary that is not signed by Apple for App Store distribution   
      or by a provisioning profile that explicitly authorizes that device.   
      There is no path for running unsigned code on consumer iOS builds.   
      
   Because of these mechanisms, an iOS IPA is not a portable software   
   artifact. It is a cryptographically-constrained container that can only   
   be installed when Apple authorizes the transaction for a specific Apple   
   ID on a specific device class.   
      
   So yes, your apps appear on a new device during an upgrade, but only   
   because Apple reissues new, device-specific builds. You are not   
   transferring the app itself, and you cannot reuse or redistribute the   
   IPA the way you can on Windows, Android, or Linux.   
      
   The core difference is that iOS is the only mainstream consumer   
   operating system where even free applications cannot be freely copied,   
   shared, or executed across devices without the platform owner's explicit   
   cryptographic approval.   
      
   Apple's behavior isn't arbitrary, as it's the result of a design philosophy   
   that treats all executable code on consumer iOS devices as something that   
   must be cryptographically authorized by Apple. Everything else flows from   
   that.   
      
   Your Apple ID is embedded into every IPA you install from the App Store.   
   No other common consumer operating systrem does that. Just iOS.   
      
   HINT: Not even macOS inserts your Apple ID into every app you install.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)