In this paper, we analyze smartphone user authentication methods that have been proposed earlier. We
also introduce various types of recent social engineering attacks, and analyze the security strength of
existing methods against social engineering attacks. Then, we propose an application adaptive pattern-based
user authentication method with enhanced security safety compared to the conventional methods. The
proposed method improves security vulnerability of existing layered pattern authentication method. In our
method, instead of the partial pattern information recorded in the layer used in the existing layered pattern
authentication method, a complete pattern is registered from one to n layers. Number of complete pattern
information can be used corresponding to various application requirements, and one or a number of patterns
can be used for each application, and thus it can provide differentiated security strength and user
convenience for each application.