I. Introduction  
II. Related Works  
III. Password in Remote User Authentication  
IV. Password Cracking Methods  
A. Traditional Password Cracking Methods  
B. Import Technology of Other Literature  
C. Probabilistic Context-Free Grammars  
V. Countermeasures for Password Cracking  
D. Password Design Stage  
E. After the Generation of Passwords  
VI. Conclusions and Future Work