# Android sharedUserId ## Identification Android's historical `sharedUserId` mechanism allowed suitably signed packages to share a Linux UID and, consequently, aspects of data and permission identity. The mechanism is deprecated because it tightly couples packages and complicates package-manager behavior. ## Notebook evidence [[Scanned_20260730-1806#Page 22 — `Scanned_20260730-1806.pdf`, PDF page 22|PDF page 22]] records shared UID as a package-state signal. [[Scanned_20260730-1806#Page 26 — `Scanned_20260730-1806.pdf`, PDF page 26|PDF page 26]] records `shared user id` beside `android.uid.system` and `coreApp=True`. ## Evidentiary boundary A declared shared UID does not establish that unrelated packages can join it. Platform signature, installation context, OS version, and the actual assigned UID must be preserved. ## Relationships [[android.uid.system]] · [[Android Package State Legend]] · [[System Privilege]].