The document discusses weaknesses in current authentication systems like textual passwords being vulnerable to dictionary attacks. It then introduces 3D passwords as a proposed multifactor authentication scheme. 3D passwords combine existing authentication methods like passwords, biometrics, etc. into a 3D virtual environment. Users authenticate by navigating and interacting with objects in the environment in a sequence that makes up their unique 3D password. The design of the virtual environment and selected objects determine the large password space, making 3D passwords more secure against guessing attacks.