Validating and writing system software to the filesystem
Android uses Security-Enhanced Linux (SELinux) to apply access control policies and establish mandatory access control (mac) on processes.See Security-Enhanced Linux in Android for details.This approach is different from other operating systems (including the traditional Linux configuration), where multiple applications run with the same user permissions. The kernel enforces security between applications and the system at the process level through standard Linux facilities, such as user and group IDs that are assigned to applications.
The foundation of the Android platform is the Linux kernel.
Android does not prevent a user or application with root permissions from modifying the operating system, kernel, or any other application.
In general, root has full access to all applications and all application data.
These include implementations of standard and commonly used cryptographic primitives such as AES, RSA, DSA, and SHA.
Additionally, APIs are provided for higher level protocols such as SSL and HTTPS.