  With the rapid development of internet technologies, social networks, and
other related areas, user authentication becomes more and more important to
protect the data of users. Password authentication is one of the widely used
methods to achieve authentication for legal users and defense against
intruders. There have been many password-cracking methods developed during the
past years, and people have been designing countermeasures against password
cracking all the time. However, we find that the survey work on password
cracking research has not been done very much. This paper is mainly to give a
brief review of the password cracking methods, import technologies of password
cracking, and the countermeasures against password cracking that are usually
designed at two stages including the password design stage (e.g. user
education, dynamic password, use of tokens, computer generations) and after the
design (e.g. reactive password checking, proactive password checking, password
encryption, access control). The main objective of this work is to offer the
abecedarian IT security professionals and the common audiences some knowledge
about computer security and password cracking and promote the development of
this area. Keywords- Computer security; User authentication; Password cracking;
Cryptanalysis; Countermeasures
