With the continuous development of functionalities and the expansion of applications, smartphones are facing many security threats. The objectives of this supplement are to protect the personal privacy of users and to improve information security of smartphones.

This supplement identifies smartphone threats which are categorized into vulnerabilities and attacks. In order to satisfy such security objectives, this supplement specifies a hierarchical security framework and relevant security considerations for smartphones. With regard to the security framework, this supplement provides necessary security solutions through system improvements and security tools.