In this paper, we conduct a comprehensive survey of the existing graphical password techniques. We classify these techniques into two categories: recognition-based and recall-based approaches. We discuss the strengths and limitations of each method and point out the future research directions in this area. We also try to answer two important questions: ¡°Are graphical passwords as secure as text-based passwords?¡±; ¡°What are the major design and implementation issues for graphical passwords?¡± This survey will be useful for information security researchers and practitioners who are interested in finding an alternative to text-based authentication methods.
